Formation Of Intermediates Research Articles

Kinetics of silica-assisted pyro-hydrolysis of CaCl2 waste for the recovery of hydrochloric acid (HCl): Effect of interaction between CaCl2 and SiO2

Pyro-hydrolysis of CaCl2 waste for HCl acid regeneration is a circular process enabling the sustainable development of the critical energy mineral extraction industry. However, the lack of detailed kinetic information has posed challenges in implementing this technology. An acidic additive such as silica (i.e., SiO2) is essential to make this reaction thermodynamically available, yet its reaction kinetics are still unknown. This study aims to reveal the detailed reaction kinetics of the SiO2-assisted pyro-hydrolysis of CaCl2 under two typical industrial settings for the feeding of reactants, physical mixing of powders and spray feeding where CaCl2 solution is expected to initially undertake drying and subsequently deposit onto the solid silica powders for a close contact. The isothermal experiment results revealed that the HCl release rate is strongly temperature-dependent. Comparatively, the CaCl2-deposited silica demonstrated a significantly faster release of HCl than the physically mixed sample, achieving 92% HCl release within 30 min at 800 °C. SEM analysis confirmed a closer inter-particle contact for the CaCl2-deposited sample, which is responsive to the accelerated HCl release. In addition, the experimental results were successfully fitted by a variable activation energy model which discovered a steady increase of the activation energy with the progression of the HCl release for both feedstock modes. This is primarily due to the continuous change on the formation of intermediates. The model also confirmed a lower activation energy for the CaCl2-deposited sample than its physically mixed counterpart at any given conversion extent of CaCl2. In contrast, for the physically mixed sample, the loose inter-particle contact led to the formation of a stable intermediate, Ca(OH)Cl, which can readily reverse to CaCl2, thereby slowing down the overall HCl release rate.

Design and fabrication of g-C3N4/Bi2S3 heterojunction photocatalysts for efficient organic pollutant degradation and antibacterial activity

Developing highly effective photocatalysts is essential in environmental remediation and sustainable manufacturing. In this study, a carbon-based semiconductor nanocomposite (g-C3N4/Bi2S3) was effectively prepared via a hydrothermal approach. Comprehensive physicochemical characterizations were active to assess the morphological, structural, and photochemical attributes of the fabricated g-C3N4/Bi2S3 nanocomposites using microscopic and spectrophotometric analyses while the intermediate products formation was assessed through GC-MS analysis. Photocatalytic degradation performance was evaluated against Reactive Black 5 (RB5) and Indigo Carmine (IC) dyes. The g-C3N4/Bi2S3 nanocomposites exhibited remarkable photodegradation efficiency compared with pure g-C3N4 and Bi2S3 catalysts, achieving 95.6 % degradation for IC and 97.5 % for RB5 after 120 min of Ultraviolet A irradiation (UVA). This excellent photocatalytic activity demonstrates the potential of g-C3N4/Bi2S3 nanocomposites for future employment in visible-light-driven wastewater treatment. The mechanism of g-C3N4/Bi2S3 NCs photocatalysis involves efficient charge separation, active site interactions, electron and hole transfer, and subsequent oxidative removal of organic pollutants, revealing the NCs suitability for sustainable environmental applications. Furthermore, the effectiveness of the g-C3N4/Bi2S3 nanocomposites in combating Streptococcus mutans and Enterococcus faecalis was appraised under UVA light exposure to determine their antibacterial properties.

DIFFERENT ROUTES FOR THE SYNTHESIS OF BENZALDEHYDE-BASED DIHYDROPYIMIDINONES VIA BIGINELLI REACTION

Multicomponent reactions involving three or more reactants are commonly used to prepare dihydropyrimidinone with various bioactivities. This study reports the different routes for the synthesis of benzaldehyde-based dihydropyrimidinone via the Biginelli reaction and investigates the yield of the obtained products. The synthesis was performed via routes A, B, C, D, and E based on the formation of iminium, enamine, and Knoevenagel intermediates between urea, benzaldehyde, and ethyl acetoacetate. Route A, through a one-pot reaction via iminium, produced dihydropyrimidinone with a yield of 58%. The product from route B via iminium was obtained in 62% yield. Route C and D occurred via enamine at room temperature, and reflux gave the product 31% and 40% yield, respectively. Route E involving Knoevenagel intermediate provided the product in a 38% yield. 1H NMR, FTIR, and MS spectroscopic techniques were used for structure elucidation.

Photocatalyzed Amination of Alkyl Halides to Access Primary Amines.

We demonstrate that oxime ester derivatives can be used as both a halogen atom transfer (XAT) agent and an imine source under photocatalytic conditions, allowing the radical amination of alkyl halides, resulting in the formation of a broad scope of imines. Hydrolysis of the latter gives direct access to the corresponding primary amines. Mechanistically, the reaction is believed to proceed through the formation of aryl radical intermediates, which are responsible for the activation of alkyl halides via XAT.

Origins of Selectivity in Glycosylation Reactions with Saccharosamine Donors.

A combination of DFT calculations and experiments is used to describe how the selection of a promoter can control the stereochemical outcome of glycosylation reactions with the deoxy sugar saccharosamine. Depending on the promoter, either α- or β-linked reactive intermediates are formed. These studies show that differential modes of activation lead to the formation of distinct intermediates that undergo highly selective reactions through an SN2-like mechanism.

Co3O4 as an efficient passive NOx adsorber for emission control during cold-start of diesel engines

The Co3O4 nanoparticles, dominated by a catalytically active (110) lattice plane, were synthesized as a low-temperature NOx adsorbent to control the cold start emissions from vehicles. These nanoparticles boast a substantial quantity of active chemisorbed oxygen and lattice oxygen, which exhibited a NOx uptake capacity commensurate with Pd/SSZ-13 at 100 °C. The primary NOx release temperature falls within a temperature range of 200-350 °C, making it perfectly suitable for diesel engines. The characterization results demonstrate that chemisorbed oxygen facilitate nitro/nitrites intermediates formation, contributing to the NOx storage at 100 °C, while the nitrites begin to decompose within the 150-200 ºC range. Fortunately, lattice oxygen likely becomes involved in the activation of nitrites into more stable nitrate within this particular temperature range. The concurrent processes of nitrites decomposition and its conversion to nitrates results in a minimal NOx release between the temperatures of 150–200 °C. The nitrate formed via lattice oxygen mainly induces the NOx to be released as NO2 within a temperature range of 200–350 °C, which is advantageous in enhancing the NOx activity of downstream NH3-SCR catalysts, by boosting the fast SCR reaction pathway. Thanks to its low cost, considerable NOx absorption capacity, and optimal release temperature, Co3O4 demonstrates potential as an effective material for PNA applications.

Ligand-Centered Photocatalytic Hydrogen Production in an Axially Capped Rh2(II,II) Paddlewheel Complex with Red Light.

A new series of Rh2(II,II) complexes with the formula cis-[Rh2(DTolF)2(bpnp)(L)]2+, where bpnp = 2,7-bis(2-pyridyl)-1,8-naphthyridine, DTolF = N,N'-di(p-tolyl) formamidinate, and L = pdz (pyridazine; 2), cinn (cinnoline; 3), and bncn (benzo[c]cinnoline; 4), were synthesized from the precursor cis-[Rh2(DTolF)2(bpnp)(CH3CN)2]2+ (1). The first reduction couple in 2-4 is localized on the bpnp ligand at approximately -0.52 V vs Ag/AgCl in CH3CN (0.1 M TBAPF6), followed by reduction of the corresponding diazine ligand. Complex 1 exhibits a Rh2(δ*)/DTolF → bpnp(π*) metal/ligand-to-ligand charge-transfer (1ML-LCT) absorption with a maximum at 767 nm (ε = 1800 M-1 cm-1). This transition is also present in the spectra of 2-4, overlaid with the Rh2(δ*)/DTolF → L(π*) 1ML-LCT bands at 516 nm in 2 (L = pdz), 640 nm in 3 (L = cinn), and 721 nm in 4 (L = bncn). Complexes 2 and 3 exhibit Rh2(δ*)/DTolF → bpnp 3ML-LCT excited states with lifetimes, τ, of 3 and 5 ns, respectively, in CH3CN, whereas the lowest energy 3ML-LCT state in 4 is Rh2(δ*)/DTolF → bncn in nature with τ = 1 ns. Irradiation of 4 with 670 nm light in DMF in the presence of 0.1 M TsOH (p-toluene sulfonic acid) and 30 mM BNAH (1-benzyl-1,4-dihydronicotinamide) results in the production of H2 with a turnover number (TON) of 16 over 24 h. The axial capping of the Rh2(II,II) bimetallic core with the bpnp ligand prevents the formation of an Rh-H hydride intermediate. These results show that the observed photocatalytic reactivity is localized on the bncn ligand, representing the first example of ligand-centered H2 production.

Oral magnesium prevents acetaminophen-induced acute liver injury by modulating microbial metabolism

Acetaminophen overuse is a common cause of acute liver failure (ALF). During ALF, toxins are metabolized by enzymes such as CYP2E1 and transformed into reactive species, leading to oxidative damage and liver failure. Here, we found that oral magnesium (Mg) alleviated acetaminophen-induced ALF through metabolic changes in gut microbiota that inhibit CYP2E1. The gut microbiota from Mg-supplemented humans prevented acetaminophen-induced ALF in mice. Mg exposure modulated Bifidobacterium metabolism and enriched indole-3-carboxylic acid (I3C) levels. Formate C-acetyltransferase (pflB) was identified as a key Bifidobacterium enzyme involved in I3C generation. Accordingly, a Bifidobacterium pflB knockout showed diminished I3C generation and reduced the beneficial effects of Mg. Conversely, treatment with I3C or an engineered bacteria overexpressing Bifidobacterium pflB protected against ALF. Mechanistically, I3C bound and inactivated CYP2E1, thus suppressing formation of harmful reactive intermediates and diminishing hepatocyte oxidative damage. These findings highlight how interactions between Mg and gut microbiota may help combat ALF.

Organocatalytic Synthesis of 2,3,4,9‐Tetrahydro‐1H‐carbazole Embedded Styrene Atropisomers

AbstractHerein we report the first synthesis of tetrahydrocarbazole embedded styrene atropisomers via the reaction between 1‐(aryl‐ethynyl)‐naphthalen‐2‐ol and 2,3,4,9‐tetrahydro‐1H‐carbazole. The reaction proceeds through in situ vinylidene ortho‐quinone methide (VQM) intermediate formation. The styrene derivatives were obtained in good to high yields with high diastereoselectivities with a catalytic amount of PTSA. A catalytic asymmetric version is also reported.

In situ chlorpyrifos (CPF) degradation by Acrobeloides maximus: Insights from chromatographic analysis

The objective of this study was to evaluate the efficiency of nematodes in zooremediation of chlorpyrifos (CPF), an organophosphate pesticide. The nematode population Acrobeloides maximus (A. maximus) was employed for bioremediation, converting CPF into non-toxic residues. Optimal growth conditions for mass production of A. maximus were achieved by maintaining a temperature of 25 °C, pH 8, and supplementing the culture medium with plant nutrients. The nematodes were then immobilized within sodium alginate beads. The efficacy of the degradation process was assessed using various analytical techniques, including UV-Visible spectroscopy, HPTLC, FTIR, and LC-MS, confirming the successful breakdown of CPF. The bioreactor demonstrated a complete degradation efficiency of CPF exceeding 99%. Additionally, LC-MS analysis was conducted to elucidate the degradation pathway based on the formation of intermediates. These results underscore the potential of A. maximus as a sustainable organism for addressing environmental contamination arising from CPF pesticide.

Papaia fermentada: estratégias para monitorizar e melhorar a fermentação das amostras - estudo preliminar

Introduction: Fermented papaya is known as a nutraceutical, with a unique composition and several health benefits. Its fermentation, being a central process of metabolism, converts the sugars in the fruit into alcohols or acids, with the intermediate formation of pyruvic acid. However, there is a lack of control and uniformity in terms of processes. Objectives: Carry out fermentation cycles of papaya in order to determine which conditions contribute to improving the pyruvic acid content and verify if there is any change of it after freezing preservation. Methodology: The papaya was washed with distilled water and cut into small cubes. About a quarter of each fruit was divided into two sterile flasks, adding ultrapure water, and placing it at 30°C. The flasks were manually shaken every 24 hours, an aliquot was taken for pH measurement. At the end of each fermentation cycle, the sample was subjected to centrifugation followed by gravity filtration and storage at -20°C. At the time of analysis, the aliquots were thawed, and the pH was measured again. The sodium pyruvate content (sodium salt of pyruvic acid) was quantified through a method adapted from another study and validated by this research team. The various fermentation cycles were carried out in duplicate, with changes in the fermentation conditions. Results: The highest content of sodium pyruvate was obtained at the end of the fermentation cycle where the whole fruit (pulp, peel and seeds) was used with sucrose supplementation (1 g.L-1). This indicates that the peel and seeds of papaya, due to their phytochemical composition, have constituents that improve the fermentation process while reducing food waste. The lowest content of sodium pyruvate was obtained on the second day of the fermentation cycle where only fresh papaya pulp and seeds were used, confirming that the presence of the peel is fundamental, probably due to the existence of autochthonous flora in the fruit that contributes to the fermentation process. Furthermore, it was also possible to verify that the pH does not change with the freezing process, indicating that there was no alteration of the pyruvic acid content during the preservation period. Conclusion: It was found that the fermentation conditions that promote a higher content of pyruvic acid is using the whole fruit and sucrose, at 30°C, for 7 days. However, other temperatures, as well as other fermentation conditions, should still be tested in order to understand if the fermentation process can be improved.

Density Functional Theory Investigation of Temperature-Dependent Properties of Cu-Nitrogen-Doped Graphene as a Cathode Material in Fuel Cell Applications

In this study, density functional theory (DFT) was used to investigate the influence of temperature on the performance of a novel Cu-nitrogen-doped graphene Cu2-N8/Gr nanocomposite as a catalyst for the oxygen reduction reaction (ORR) in fuel cell applications. Our DFT calculations, conducted using Gaussian 09w with the 3–21G/B3LYP basis set, focus on the Cu-nitrogen-doped graphene nanocomposite cathode catalyst, exploring its behavior at three distinct temperatures: 298.15 K, 353.15 K, and 393.15 K, under acidic conditions. Our analysis of formation energies indicates that the structural stability of the catalyst remains unaffected as the temperature varies within the potential range of 0–7.21 V. Notably, the stability of the ORR steps experiences a marginal decrease with increasing temperature, with the exception of the intermediate OH + H2O (*OH + H + *OH). Interestingly, the optimization reveals the absence of single OH and H2O intermediates during the reactions. Furthermore, the OH + H2O step is optimized to form the OH + H + OH intermediate, featuring the sharing of a hydrogen atom between dual OH intermediates. Free energy calculations elucidate that the catalyst supports spontaneous ORR at all temperatures. The highest recorded maximum cell potential, 0.69 V, is observed at 393.15 K, while the lowest, 0.61 V, is recorded at 353.15 K. In particular, the Cu2-N8/Gr catalyst structure demonstrates a reduced favorability for the H2O2 generation at all temperatures, resulting in the formation of dual OH intermediates rather than H2O2. In conclusion, at 393.15 K, Cu2-N8/Gr exhibits enhanced catalyst performance compared to 353.15 K and 298.15 K, making it a promising candidate for ORR catalysis in fuel cell applications.

Boosting promote C2 products formation in electrochemical CO2 reduction reaction via phosphorus-enhanced proton feeding

Electrochemical CO2 reduction reaction (CO2RR) using renewable energy to produce valuable multicarbon (C2+) products is a promising approach for carbon emission reduction. In this work, we propose a new strategy to enhance the formation of hydrogen-containing intermediates using the excellent abilities of proton transportation and electronic structure modification of phosphorus (P). To realize this, an in situ electrodeposition method was proposed to prepare P-doped Cu catalysts. It was found that the electrodeposition potential significantly impacts the structure and catalytic performance of P-Cu catalysts. Specifically, the catalyst obtained at − 0.5 V vs. Ag/AgCl exhibited exceptional performance for CO2RR towards C2+ products, achieving a Faradaic efficiency (FE) of ∼ 80.2 % and a partial current density of 40.4 mA cm−2 in an H-type cell. Furthermore, the catalyst demonstrated stability for at least 12 h. Experimental and density functional theory (DFT) studies revealed that the free energy of the hydrogenated process could be significantly reduced by the excellent proton transport ability of P, and the interaction of Cu with the unpaired electrons of carbon could be improved, leading to excellent adsorption ability of Cu for the intermediates and high FE of C2+ products.

Assessing atmospheric and oceanic teleconnections between the eastern and western Mediterranean over the past 8000 years

Holocene climate records from the Mediterranean are marked by pervasive millennial to centennial-scale climate variability. Here, we investigate East-West Mediterranean atmospheric and oceanic teleconnections by computing phase-relationships between oxygen isotope (δ18O) records generated on Soreq (East) and Chorchia (West) spelaeothems, as well as between δ18O and carbon isotope (δ13C) records from planktonic and benthic foraminifera from core PS009PC (East, Levantin Basin), ODP Site 963D (Central, Sicily Strait), and core KESC9-14 (West, Ligurian Basin). These marine sites are all located at intermediate water depths (560–460 m depth). Hence, the benthic foraminiferal δ18O records reflect mainly the intermediate ocean temperature/δ18O of the water mass, and the benthic δ13C is a proxy for the intensity of water flowing at the studied depth called Levantine Intermediate Water (LIW). For both western and eastern cores, the planktonic stable isotopic records reflect the climate-induced activity of the nearby river system. We find broadly in-phase relationships between the spelaeothem δ18O records and between the planktonic δ18O and δ13C records at most multi-centennial and millennial periodicities. This is indicative of closely linked (hydro-) climatic conditions in Southern Europe, the Levant, and North Africa over the last 8000 years. Conversely, at intermediate water depths, we find a distinct out-of-phase relationship between the East/Central and West Mediterranean benthic δ18O and δ13C records at 1000–2000 years periodicities. We interpret this see-saw pattern as indicative of a persistent regional influence of LIW on oceanographic conditions in the intermediate depths of the eastern basin. Conversely, we suggest a strong influence of the modified Atlantic Ocean inflow (MAW) in the intermediate water formation in the Western Mediterranean (‘Winter Intermediate Water’; WIW). This WIW overprints, at least partially, the LIW signal that reaches the western Mediterranean causing the out-of-phase relationship between the east and the west oceanographic signals at intermediate depths.

Iron phthalocyanine hollow architecture enabled ammonia production via nitrate reduction to achieve 100 % Faradaic efficiency

Eight electron nitrate (NO3–) reduction to ammonia (NH3) offers a cost–effective and energy efficient route than the Haber–Bosch process. The state of art electrocatalysts for nitrate reduction shows potential activity, albeit suffering from poor Faradaic efficiency, kinetically sluggish multi electron–proton process, and competitive hydrogen evolution reaction. Herein, we present a hollow iron phthalocyanine (FePc) rectangular nanotube (RNTs) electrocatalyst with 100 % Faradaic efficiency and 35067.09 µg h–1 mgcat–1 ammonia yield, which is 3.5 times higher than that of FePc nanorods. One-of-a-kind hollow nanostructure has Fe-N4 active motif sites necessary for NO3– activation, dissociation, specific intermediate formation, and interaction, resulting in the energy-efficient generation of NH3, according to in-situ research combined with theoretical analysis of molecular scale reaction mechanism. These unique results, coupled with the monitoring of pH changes in real time during electrolysis, open up new possibilities for progressive ammonia production with reduced carbon footprint.

Nickel-Catalyzed Chemo- and Enantioselective Hydrogenation and Deuteration of α,β-Unsaturated Ketimines Using Alcohols: Synthesis of Deuterated Chiral Allylic Amines.

A nickel-catalyzed chemoselective asymmetric transfer hydrogenation of α,β-unsaturated ketimines using ethanol as a hydrogen donor under mild conditions that avoid using high-pressure hydrogen gas was developed. With this catalyst, C1-selective deuterated chiral allylic amines were efficiently synthesized using only stoichiometric 2-propanol-d8. Mechanism studies demonstrated the formation of a nickel hydride intermediate.

Treatment of 2-naphthalene sulfonate by free and immobilized cells of indigenous isolate Comamonas sp. C2 and toxicity evaluation of biotransformed sample

An indigenous bacterial strain Comamonas sp. C2, capable of utilizing 2-naphthalene sulfonate (2-NS) as a sole source of carbon, was isolated after enrichment of microbial diversity present in sample collected from sewage treatment plant (STP) receiving untreated or partially treated effluent from textile industries. The isolate was able to degrade 100 mg/L of 2-NS, when grown in sulfur free minimal salt medium (SFMSM), after an incubation of 8 h. The release of sulfite/sulfate ions during biotransformation, assay of protocatechuate 4, 5-dioxygenase activity and formation of metabolic intermediates like salicylaldehyde, protocatechuate and 2-hydroxy-4-carboxy-muconatesemialdehyde in the biologically treated sample indicated to the meta-cleavage of aromatic ring of 2-NS. An immobilized-cell plug flow bioreactor (PFR) was developed and evaluated for its efficiency to treat simulated feed supplemented with 100 mg/L of 2-NS. The cells of C2 were immobilized on pieces of polyurethane foam (PUF) and refractory brick pieces (RBP). The PFR, when operated at an HRT of 36 h, achieved complete degradation of 100 mg/L of 2-NS corresponding to 89% lowering of COD. The reduction in overall toxicity of 2-NS after biological treatment was evaluated using plant (Triticum aestivum and Vigna radiata) and animal (freshwater fish Channa punctatus) models, exposed to both untreated and PFR treated samples. To the best of our knowledge, there are no similar reports on exploitation of the metabolic potential of Comamonas sp. in 2-NS degradation and validation of the biological transformation by toxicity analysis.

In situ observation of a stepwise [2 + 2] photocycloaddition process using fluorescence spectroscopy

Using highly sensitive and selective in situ techniques to investigate the dynamics of intermediates formation is key to better understand reaction mechanisms. However, investigating the early stages of solid-state reactions/transformations is still challenging. Here we introduce in situ fluorescence spectroscopy to observe the evolution of intermediates during a two-step [2 + 2] photocycloaddition process in a coordination polymer platform. The structural changes and kinetics of each step under ultraviolet light irradiation versus time are accompanied by the gradual increase-decrease of intensity and blue-shift of the fluorescence spectra from the crystals. Monitoring the fluorescence behavior using a laser scanning confocal microscope can directly visualize the inhomogeneity of the photocycloaddition reaction in a single crystal. Theoretical calculations allow us to rationalize the fluorescence behavior of these compounds. We provide a convenient strategy for visualizing the solid-state photocycloaddition dynamics using fluorescence spectroscopy and open an avenue for kinetic studies of a variety of fast reactions.

One‐Pot Conversion of Benzyl Alcohols to N‐Protected Anilines and Alkyl Alcohols to Carbamoyl Azides

AbstractOne‐pot, scalable procedures converting benzylic or aliphatic alcohols to various N‐functionalized amines are reported in 38–83 % overall yields. These multi‐step conversions are relatively economic and involve the oxidative formation of acid chloride intermediates and the Curtius rearrangement of acyl azides. Notable aspects of economy include: (1) the use of a relatively green solvent (chlorobenzene) that tolerates both ionic and radical reactions, without the need for rigorously dry or O2‐free conditions; (2) the use of minimal amounts of trichloroisocyanuric acid (TCCA) as a cheap and green chlorinating agent to oxidize the alcohol starting materials and then transform the aldehyde intermediates to acid chlorides under photoirradiation for azide addition; (3) the efficient capture of isocyanate intermediates by alcohol or azide nucleophiles providing N‐protected anilines or N‐protected alkylamines, respectively, the latter of which was employed in the synthesis of an anti‐dementia drug, memantine hydrochloride, over two purification steps.

Organocatalytic Diastereoselective (4 + 1) Cycloaddition of o-Hydroxyphenyl-Substituted Secondary Phosphine Oxides.

The first organocatalytic diastereoselective (4 + 1) cycloaddition of o-hydroxyphenyl-substituted secondary phosphine oxides (SPOs) has been established, which makes use of o-hydroxyphenyl substituted SPOs as suitable four-atom phosphorus-containing 1,4-dinucleophiles and 3-indolylformaldehydes as competent 1,1-dielectrophiles under Bro̷nsted acid catalysis. The reaction mechanism was suggested to involve the formation of 3-indolylmethanol intermediates and vinyliminium intermediates, which played an important role in controlling the reactivity and diastereoselectivity of the (4 + 1) cycloaddition under Bro̷nsted acid catalysis. By this approach, a series of benzo oxaphospholes bearing P- and C-stereocenters were synthesized in moderate to good yields (50%-95% yields) with excellent diastereoselectivities (all >95:5 dr). This reaction not only represents the first organocatalytic diastereoselective (4 + 1) cycloaddition of o-hydroxyphenyl-substituted SPOs but also provides an efficient and diastereoselective method for the construction of phosphorus-containing benzo five-membered heterocyclic skeletons bearing both P-stereocenter and C-stereocenter.