Carbonyl Compounds Research Articles

Vinyltriarylbismuthonium Salts: Powerful Vehicles for α-Vinylation of Carbonyl Compounds.

α-Vinyl-carbonyl compounds are a class of orthogonally functionalized molecules, wherein the intrinsic C═O and C═C bonds can be used to unlock distinctly different reactivities. In this report, we present a simple method for the direct α-vinylation of carbonyl compounds utilizing vinyltriarylbismuthonium ("Vinyl-Bis") salts, which are stable and readily preparable on a decagram scale. This transformation is accomplished efficiently through the reaction of an in situ generated Li-enolate intermediate with a Vinyl-Bis reagent, leading to the formation of α-vinylated carbonyl compounds in good to excellent yields and with a remarkably broad substrate scope. Critically, this vinylation method is effective for enolates generated via numerous methods, enabling the sequencing of reactions that generate enolates with the vinylation step and the ready synthesis of diversely functionalized compounds, thereby underscoring the versatility and practicality of this method. Analogous reactions of discrete Li-enolates with other vinyl units and with aryl groups are also demonstrated.

Synthesis of Multisubstituted 2,3-Allenamides via Palladium-Catalyzed Carbonylation of Propargylic Esters.

2,3-Allenamides are an important class of unsaturated group-substituted carbonyl compounds. A palladium-catalyzed aminocarbonylation of propargyl acetates with amines for the synthesized tri-/tetrasubstituted 2,3-allenamides has been developed. A broad range of tri-/tetrasubstituted 2,3-allenamides have been prepared from propargyl acetates in good to excellent yields. The reaction featured mild reaction conditions and good functional group tolerance. The applicability of this methodology was further highlighted by the late-stage modification of several natural products and pharmaceuticals.

Multielectron Reduction of Esters by a Diazabenzacenaphthenium Photoredox Catalyst.

A novel diazabenzacenaphthenium photocatalyst, N-BAP, with high photoredox abilities and visible-light absorption was designed and prepared in one step. Under visible-light irradiation, N-BAP promoted the four-electron reduction of esters in the presence of ammonium oxalate as a "traceless reductant" to generate carbinol anion intermediates that underwent protonation with water to give the corresponding alcohols. The resulting carbinol anions also exhibited nucleophilic reactivity under the photocatalytic conditions to undergo a 1,2-addition to a second carbonyl compound, affording unsymmetric 1,2-diols.

A refined picture of the native amine dehydrogenase family revealed by extensive biodiversity screening

Native amine dehydrogenases offer sustainable access to chiral amines, so the search for scaffolds capable of converting more diverse carbonyl compounds is required to reach the full potential of this alternative to conventional synthetic reductive aminations. Here we report a multidisciplinary strategy combining bioinformatics, chemoinformatics and biocatalysis to extensively screen billions of sequences in silico and to efficiently find native amine dehydrogenases features using computational approaches. In this way, we achieve a comprehensive overview of the initial native amine dehydrogenase family, extending it from 2,011 to 17,959 sequences, and identify native amine dehydrogenases with non-reported substrate spectra, including hindered carbonyls and ethyl ketones, and accepting methylamine and cyclopropylamine as amine donor. We also present preliminary model-based structural information to inform the design of potential (R)-selective amine dehydrogenases, as native amine dehydrogenases are mostly (S)-selective. This integrated strategy paves the way for expanding the resource of other enzyme families and in highlighting enzymes with original features.

Synthesis and utility of N-boryl and N-silyl enamines derived from the hydroboration and hydrosilylation of N-heteroarenes and N-conjugated compounds.

Catalytic hydroboration and hydrosilylation have emerged as promising strategies for the reduction of unsaturated hydrocarbons and carbonyl compounds, as well as for the dearomatization of N-heteroarenes. Various catalysts have been employed in these processes to achieve the formation of reduced products via distinct reaction pathways and intermediates. Among these intermediates, N-silyl enamines and N-boryl enamines, which are derived from hydrosilylation and hydroboration, are commonly underestimated in this reduction process. Because these versatile intermediates have recently been utilized in situ as nucleophilic reagents or dipolarophiles for the synthesis of diverse molecules, an expeditious review of the synthesis and utilization of N-silyl and N-boryl enamines is crucial. In this review, we comprehensively discuss a wide range of hydrosilylation and hydroboration catalysts used for the synthesis of N-silyl and N-boryl enamines. These catalysts include main-group metals (e.g., Mg and Zn), transition metals (e.g., Rh, Ru, and Ir), earth-abundant metals (e.g., Fe, Co, and Ni), and non-metal catalysts (including P, B, and organocatalysts). Furthermore, we highlight recent research efforts that have leveraged these versatile intermediates for the synthesis of intriguing molecules, offering insights into future directions for these invaluable building blocks.

The combination of tetramethylpyrazine and vitamin A acid in the treatment of skin photoaging by activating the HIF-1α pathway.

Skin photoaging is a skin degenerative disease that causes patients to develop malignant tumors. The existing clinical treatment of photoaging has limitations. This greatly reduces the recovery rate of photoaging patients. Studies have confirmed that Ligusticum wallichii Franch (LWF) monomer tetramethylpyrazine (TMP) alleviates various skin diseases. The combination of traditional Chinese medicine and Western medicine helps with this process. Our research aimed to explore the specific treatment mode and molecular mechanism of TMP in treating skin photoaging. CCK-8 assays were used to evaluate the activity and toxicity of HaCaT cells. β-galactosidase aging, Carbonyl compound and nitrosylated tyrosine assays were used to analyze the aging of HaCaT cells. ROS assays and ELISA were used to analyze the enrichment of ROS. The molecular docking experiment analyzed the binding of TMP and HIF-1α. qRT-PCR and Western blot were used to detect the activation of skin aging-related pathways. HE staining was used to analyze the thickness of the stratum corneum skin on the back skin of mice. 200μg/L LWF alleviates cellular photoaging and mouse skin photoaging by reducing ROS enrichment. Its monomer TMP plays an important role in this process. The combination of TMP and HIF-1α accelerates the degradation of ROS by activating the Nrf2/ARE signaling pathway. This process reduces the apoptosis of cells damaged by light. In addition, we also found that the combination of TMP and retinoic acid (RA) is more beneficial for the treatment of skin damage caused by light in mice. The combination therapy of TMP and RA alleviates skin oxidative stress response through overexpression of HIF-1α. This plan is beneficial for the treatment of skin photoaging.

Effect of the addition of black garlic on the quality parameters of jerked beef meat with pork.

The objective of this work was to evaluate the effects of the replacement of nitrite by natural antioxidants from black garlic (BG) on the quality parameters of jerked beef meat with pork for 60 days. Four formulations were prepared: control, 0.02% of sodium nitrite in brine curing, w/v (CON); 1.5% BG in brine curing, w/v (ASU); 1.5% BG in dry curing, w/w (ASS); and 1.5% of BG in the brine curing, w/v and 1.5% of BG in dry curing, w/w (ASUS). Nutritional composition, pH, water activity, shear force, fatty acid profile, color, and oxidative stability of the formulations were analyzed. The addition of BG did not affect the nutritional composition, pH, water activity, shear force, and fatty acid profile. On the other hand, it resulted in lower weight loss after centrifugation and lower values of L* and a*. TBARS values from the 30th day of storage were lower in the ASUS formulation, while carbonyl compounds at all times were lower than in the CON formulation. Results suggest that BG was an efficient alternative to nitrite in controlling protein oxidation during storage. Thus, the use of pork for the manufacture of jerked beef can be an alternative, and black garlic can be applied as a natural additive to the replacement of nitrite. In addition, black garlic was efficient in improving the oxidative stability of the jerked beef meat with pork.

Chromium Catalyzed Asymmetric Reformatsky Reaction.

This study describes an unprecedented chromium-catalyzed asymmetric Reformatsky reaction, enabling the synthesis of chiral β-hydroxy carbonyl compounds from α-chlorinated or α-brominated esters and amides. By employing a chiral chromium/diarylamine bis(oxazoline) catalyst, we achieved relatively broad functional group tolerance. Distinct from known reports, the protocol operates under both classical and photoredox conditions, facilitated by the in-situ formation of a nucleophilic chiral chromium intermediate through a radical-polar crossover mechanism. Preliminary mechanistic insights, supported by DFT calculations, identify the nucleophilic aldehyde addition as the key stereo-determining step. This approach not only overcomes the limitations of existing Reformatsky reactions but also provides a versatile strategy for accessing complex chiral molecules.

Ultrastable Organic Anode Enabled by Electrochemically Active MXene Binder toward Advanced Potassium Ion Storage.

Conjugated carbonyl compounds are regarded as promising organic anode materials for potassium ion batteries (PIBs) due to their rich redox sites, excellent reversibility, and structural tunability, but their low electrical conductivity and severe solubility in organic electrolytes have substantially restricted their practical application. Herein, 2D MXene is utilized as an electrochemically active binder to fabricate perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) electrodes for high-performance PIBs. MXene, coupled with Super-P particles, served as a binder and conductive matrix to facilitate rapid ion and electron transport, restrain the solubility of PTCDA, promote potassium adsorption, and alleviate the volume expansion of PTCDA during potassiation. Consequently, the PTCDA electrode bonded by the MXene/Super-P system delivers excellent potassium storage performance in terms of a high capacity of 462 mAh g-1 at 50 mA g-1, superior rate capability of 116.3 mAh g-1 at 2000 mA g-1, and stable cycle performance over 3000 cycles with a low capacity decay rate of ∼0.0033% per cycle. When configured with the PTCDA@450 cathode, an all-PTCDA potassium ion full cell delivers a maximum energy density of 179.5 Wh kg-1, indicating the superiority of MXene as an electrochemically active binder to promote the practical application of organic anodes for PIBs.

Perfluoroalkylation Reactions by Electron Donor‐Acceptor Complexes: Recent Advances

AbstractThis Perspective analyses the perfluoroalkylation reactions by electron donor‐acceptor (EDA) complexes since 2018, while summarizes, in Tables , the vast majority of representative perfluoroalkylation reactions of various classes of organic compounds by EDA complexes and halogen‐bonding interactions. Numerous intriguing reaction methodologies and valuable synthetic instances have emerged. We aim to delve into these new examples comprehensively, while also contemplating the future directions in the field. Subsequent sections will elaborate on the perfluoroalkylation of (hetero)aromatic compounds, carbon‐carbon multiple bonds, perfluoroalkylation of carbonyl compounds, and perfluoroalkylation of isocyanides, covering their synthetic scope and mechanistic insights. Perfluoroalkylation reactions of (hetero)aromatic compounds by EDA complexes. Entry Substrate Complex Reaction conditions Product Ref. 1 [13] 2 [46] 3 RFI (3 equiv.) KOH (1.5 equiv.) Blue LEDs H2O, Ar, 20 h [47] 4 TEEDA (3 equiv.) CFL (25 W) THF, r.t. RF−I (3 equiv.) [48] 5 ICF2CO2Et (1.3 equiv.) Na2CO3 (1.5 equiv.) DMSO (3 mL) Ar, rt. 427 nm LED, 16 h [49] 6 TMG (2.5 equiv.) RF−I (2.5 equiv.) 23 W CFL, MeCN/Hexf (5 : 1) [42,50] 7 TMG (2.5 equiv.) RF−I (2.5 equiv.) 23 W CFL, MeCN [51] 8 Umemoto's reagent (2 equiv.) N‐methylmorpholine (2.5 equiv.) DMF, r.t. [52] 9 Cs2CO3 (2 equiv.) RF−I (3 equiv.) white light H2O (3 equiv.) DMF, r.t., 2 h [53] 10 4.5 W 450 nm laser CaCl2, MeNO2, 0 °C [3] 11 RF−I (1.5 equiv.) t‐BuONa (2 equiv.) DMF Green LEDs [54] 12 or EDA complex I−Rf (2.1 equiv.) TMEDA (2 equiv.) or DBU (2 equiv.) Blue LEDs 24 W [55,56] 13 TFE/water (1 : 1) (0.2 M) CF3SO2Na Blue LEDs r.t., 12 h [84] Perfluoroalkylation reactions of carbon‐carbon multiple bonds and constrained cyclic compounds by EDA complexes. Entry Substrate Complex Reaction conditions Product Ref. 1 Bu4NCl, Hg lamp (6 W) RF−I (1.2 equiv.) CH3OH, 1.5 h r.t, Ar [39] 2 RFI (3 equiv.) KOH (1.5 equiv.) Blue LEDs H2O, Ar, 20 h [47] 3 [57] 4 DIPEA or TMEDA or DBU or TEEDA ……..CF3I CF3−I (3 equiv.) Base (2 equiv.) MeCN or DMF or THF CFL, 25 W with DIPEA, TMEDA or TEEDA; with DBU [48,58,59] 5 Bn2NH MeCN RF−I Blue LED, r.t. [60] 6 Base, Blue LEDs DMF or THF [61] 7 I−RF H2O/toluene=9 : 1 Blue LEDs, 65 °C, 12 h [41] 8 K3PO4 (3 equiv.) RF−I (3 equiv.) CuCl (10 mol%) TMSNCS (3 equiv.) CH3CN (2 mL) Violet LEDs (24 W) Ar, 4 h [37] 9 RF−I (3 equiv.) Diphenylacetaldehyde (10 mol%) Pyrrolidine (40 mol%) DIPEA (2 equiv.) DCE (2.5 mL); O2 (0.8 eq.); Ar White LEDs (2.5 W); 24 h [44,62] 10 DIPEA,DMA Ar (trace air) Blue LEDs, rt. 36–72 h [63] 11 TMEDA Blue LEDs n‐C4F9I DMSO air, 24 h RT [64] 12 K3PO4 (2 equiv.) DABCO (1.2 equiv.) hυ (400 Watt) 50 °C CnF2n+1I (1.8 equiv.) [65–67] 13 Blue LEDs DCE, r.t. [27] 14 2,4,6‐trimethylpyridine MeCN, 60 °C Togni's reagent [68] 15 PMDETA (2 equiv.) DMSO (2 mL) N2, Blue LEDs [69] 16 Blue LEDs [70,71] 17 MeCN (0.2 M) with less than 1 % water CF3SO2Na (1 mmol) Blue LEDs [84] Perfluoroalkylation of carbonyl compounds, isocyanides and hydrazones. Entry Substrate Complex Reaction conditions Product Ref. 1 [72,73] 2 RF−I (0.2 mmol) cis‐catalyst M (20 mol%) 2,6‐lutidine (1.2 equiv.) Blue LEDs, Et2O (0.7 M) ‐10 °C, 20 h [74] 3 white light RF−I [75] 4 phase transfer catalyst Cs2CO3, C6H5Cl/8F18 (2 : 1), 25 °C, RF−I [32] 5 ambient light C4F9−I NaOH (4.1 equiv.) MeCN, R.T. [76] 6 RFI (3 equiv.) KOH (1.5 equiv.) Blue LEDs THF, Ar, 36 h [47] 7 RF−I (2 equiv.) TMEDA (2 equiv.) THF (2 mL) Blue LEDs (25 W) 30 °C, N2 [77] 8 TEEDA (1.5 equiv.) CFL (25 W) THF I−C4F9 [48] 9 Bn2NH Blue LEDs MeCN, RT RF−I [78] 10 TMG (1.5 equiv.) ambient light MeCN, RT I−RF [79] 11 Imidazole (3 equiv.) MeCN, RF−I (2 equiv.) r.t. [80]

Chromium Catalyzed Asymmetric Reformatsky Reaction

This study describes an unprecedented chromium‐catalyzed asymmetric Reformatsky reaction, enabling the synthesis of chiral β‐hydroxy carbonyl compounds from α‐chlorinated or α‐brominated esters and amides. By employing a chiral chromium/diarylamine bis(oxazoline) catalyst, we achieved relatively broad functional group tolerance. Distinct from known reports, the protocol operates under both classical and photoredox conditions, facilitated by the in‐situ formation of a nucleophilic chiral chromium intermediate through a radical‐polar crossover mechanism. Preliminary mechanistic insights, supported by DFT calculations, identify the nucleophilic aldehyde addition as the key stereo‐determining step. This approach not only overcomes the limitations of existing Reformatsky reactions but also provides a versatile strategy for accessing complex chiral molecules.

Counterintuitive chemoselectivity in the reduction of carbonyl compounds.

The reactivity of carbonyl functional groups largely depends on the substituents on the carbon atom. Reversal of the commonly accepted order of reactivity of different carbonyl compounds requires novel synthetic approaches. Achieving selective reduction will enable the transformation of carbon resources such as plastic waste, carbon dioxide and biomass into valuable chemicals. In this Review, we explore the reduction of less reactive carbonyl groups in the presence of those typically considered more reactive. We discuss reductions, including the controlled reduction of ureas, amides and esters to aldehydes, as well as chemoselective reductions of carbonyl groups, including the reduction of ureas over carbamates, amides and esters; the reduction of amides over esters, ketones and aldehydes; and the reduction of ketones over aldehydes.

Green infant formula analysis: Optimizing headspace solid-phase microextraction of carbonyl compounds associated with lipid peroxidation using GC-MS and pentafluorophenylhydrazine derivatization

The refinement and optimization of a method combining headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) was successfully performed for the first time to determine seven carbonyl and dicarbonyl compounds, including glyoxal, methylglyoxal, dimethylglyoxal, and malondialdehyde in infant formulae, related to lipid peroxidation. HS-SPME was utilized for simultaneous extraction and derivatization with pentafluorophenylhydrazine (PFPH). Critical parameters such as temperature, pH, extractive phase, and salting-out were meticulously investigated and fine-tuned by an asymmetrical 2232//9 screening design to ensure the method's efficacy and reliability. Optimal conditions included a PFPH concentration of 5 g/L, pH 5.0, head-space extraction at 60 °C within 10 min, utilizing a DVB/CAR/PDMS coating, and a 20% w/w salting-out. The analytical validation of this method, compliant with FDA guidelines, demonstrated exceptional linearity, sensitivity, specificity, precision (RSD ≤13.8%), and accuracy (84.8% ≤ recovery ≤111.5%). The metric approach AGREEprep confirms its eco-friendliness, marking a significant step towards an environmentally conscious approach in infant formula analysis. An occurrence study conducted on 25 infant formula samples revealed widespread carbonyl and dicarbonyl compounds in both powdered and liquid variants. ANOVA results exhibited variations in compound concentrations among different sample groups. Clustering analyses delineated distinct groups based on carbonyl content, indicating the potential of these compounds as markers for lipid peroxidation and food quality assessment. This method serves as a valuable tool for evaluating infant formula quality, stability towards oxidation, and safety.

Soft-templating synthesis of mesoporous MnSiOx composites as catalytic supports for Pd nanoparticles towards solvent-free oxidation of benzyl alcohol under atmospheric pressure O2

Solvent-free and liquid-phase selective oxidation of aromatic alcohols using O2 as an oxidant is a green strategy for the synthesis of aromatic aldehydes and other carbonyl compounds. Wherein, the design and preparation of heterogeneous catalysts with high activity and selectivity is a hot topic in this process. Herein, a series of manganese oxide-silica (MnSiOx) composites were synthesized using cetyltrimethylammonium bromide as a soft template. During the preparation process, the amounts of tetraethyl orthosilicate and ammonia and the calcination temperature significantly affected the textural properties and Mn cation distributions of MnSiOx. The MnSiOx composites were then employed as catalysts for Pd nanoparticles. In the solvent-free and atmospheric conditions, Pd/MnSiOx materials showed high catalytic conversions of benzyl alcohol (BZA), and the catalytic activity thereof is related to the fractions of Pd0 and Mn3+. As the reaction time and temperature are 4 h and 90 °C, the conversion of BZA (feeding dosage: 4 mL) and the selectivity of benzaldehyde are 64.8 % and 94.9 %, respectively. The catalyst can be reused at least five times without any significant loss of activity. Furthermore, the correlation between physiochemical properties and catalytic activity of Pd/MnSiOx was analyzed.

Iron‐Based Deep Eutectic Solvents: Key Players for Amide and Sulfonamide Synthesis and Alcohol Oxidation

AbstractA sustainable protocol has been devised for the oxidation of activated secondary alcohols to their corresponding carbonyl compounds, as well as their utilization as selective mono‐alkylating reagents for both amide and arylsulfonamide derivatives. These reactions proceed smoothly and in good yields (up to 98 %) when conducted in Fe‐based deep eutectic solvents (DESs), which serve dual roles as solvents and catalysts. Operating under mild (40 °C) and aerobic conditions, these transformations are completed within a 4 h time frame. A pharmacologically relevant amide derivative, specifically a PMRT1 inhibitor, has also been successfully synthesized on a 3 g‐scale utilizing a reusable FeCl3 ⋅ 6H2O/glycerol Lewis acidic DES.

Photocatalyzed one‐pot selective synthesis of γ‐(per)fluoroalkenylated α,β‐unsaturated carbonyl compounds

Photocatalyzed one‐pot selective synthesis of γ‐(per)fluoroalkenylated α,β‐unsaturated carbonyl compounds

Major generation route of cytotoxic protein adducts derived from acetaldehyde, a metabolite of alcohol

The habitual excessive consumption of alcohol has been implicated in the onset and/or progression of alcoholic-associated liver/brain diseases (ALD/ABD), lung disease, rheumatoid arthritis, and cardiac tissue injury. Alcohol (ethanol) is metabolized to acetaldehyde (AA), a two-carbon carbonyl compound that reacts with proteins to form covalent AA-protein adducts (AAPAs). We herein propose that AA reacts with liver and/or brain proteins to generate AAPAs, which contribute to alcohol-induced liver injury and neurotoxicity in vivo, respectively. The viability of hepatocytes was significantly lower in a culture treated with AAPAs than in a culture treated with Nε-(ethyl)lysine (NEL), the reduced form of Schiff bases, or a control culture. Furthermore, a correlation was observed between staining for AAPA and 4-hydroxy-2-nonenal in the liver and the severity of ALD in both rats and humans. The chronic consumption of alcohol produces AAPAs and reactive oxygen species, both of which have been implicated in the pathogenesis of ALD. Moreover, a dose-dependent increase in neuronal cell death was noted in cortical neurons incubated with AAPAs, the neurotoxicity of which was completely suppressed by an anti-AAPA antibody, but not an anti-NEL antibody. AAPA epitopes have been detected in the brains of individuals withalcohol-related brain damage. AAPAs have also been shown to contribute to the pathogenesis of ABD. The hypothesis proposed herein is that strongly cytotoxic AAPAs are iminobutane structures, which differ from the known structures of NEL. We suggest the importance of structural epitope AAPAs as toxic moieties for hepatocytes and neuronal cells in alcoholism.

Enantioselective α-Trifluoromethylthiolation of Carbonyl Compounds with AgSCF3 and Trichloroisocyanuric Acid.

We successfully developed an enantioselective trifluoromethylthiolation of structurally diverse carbonyl compounds. Trichloroisocyanuric acid and AgSCF3 were employed to generate active electrophilic trifluoromethylthio species in situ for asymmetric C-SCF3 bond formation. A broad variety of chiral SCF3-carbon nucleophiles (pyrazolones, β-keto esters, and β-keto amides) were obtained in excellent yields with high enantioselectivities (up to 92% ee) by Cinchona alkaloid derived squaramide catalysts. The reaction exhibits high efficiency, good enantioselectivity, and high functional group tolerance, which provided a novel and efficient way for asymmetric synthesis of trifluoromethylthiolated carbonyl compounds.

Preparation of Magnetically Recyclable MIL‐101‐immobilized Frustrated Lewis Pairs for the Reduction of Aldehydes and Ketones

Frustrated Lewis pairs (FLPs), composed of spatially hindered Lewis acids and bases, are promising catalysts for the catalytic hydrogenation of unsaturated organic substrates, but the lack of reusability limits their development. The functionalization of solid materials with molecular FLP is a promising method for preparing heterogeneous FLP catalysts. In this work, a magnetically recyclable FLP catalyst was successfully prepared for the reductive carbonyl compounds to the corresponding alcohols. FLP of 2‐Ph2PPhCHO/B(C6F5)3 was grafted into NH2‐MIL‐101@Fe3O4 composite material through an aldehyde‐amine condensation reaction. The as‐prepared FLP‐NH‐MIL‐101@Fe3O4 exhibited remarkable catalytic activity for aldehyde/ketone carbonyl compounds. In addition, FLP‐NH‐MIL‐101@Fe3O4 displays outstanding magnetic recyclability and can be reused 8 times without loss of activity.

Hydrogen‐Bond‐Mediated Formation of C−N or C=N Bond during Photocatalytic Reductive Coupling Reaction over CdS Nanosheets

AbstractReductive amination of carbonyl compounds and nitro compounds represents a straightforward way to attain imines or secondary amines, but it is difficult to control the product selectivity. Herein, we report the selective formation of C−N or C=N bond readily manipulated through a solvent‐induced hydrogen bond bridge, facilitating the swift photocatalytic reductive coupling process. The reductive‐coupling of nitro compounds with carbonyl compounds using formic acid and sodium formate as the hydrogen donors over CdS nanosheets selectively generates imines with C=N bonds in acetonitrile solvent; while taking methanol as solvent, the C=N bonds are readily hydrogenated to the C−N bonds via hydrogen‐bonding activation. Experimental and theoretical study reveals that the building of the hydrogen‐bond bridge between the hydroxyl groups in methanol and the N atoms of the C=N motifs in imines facilitates the transfer of hydrogen atoms from CdS surface to the N atoms in imines upon illumination, resulting in the rapid hydrogenation of the C=N bonds to give rise to the secondary amines with C−N bonds. Our method provides a simple way to control product selectivity by altering the solvents in photocatalytic organic transformations.