Intramolecular Carbonyl Research Articles

ChemInform Abstract: Synthesis of 2‐Cyclopentenone Derivatives via Palladium‐Catalyzed Intramolecular Carbonyl α‐Alkenylation.

2-Cyclopentenone derivatives have been efficiently synthesized from 5-bromo-5-hexen-2-ones via palladium-catalyzed intramolecular carbonyl α-alkenylation followed by double-bond migration under mild reaction conditions.

Synthesis of 2-Cyclopentenone Derivatives via Palladium-Catalyzed Intramolecular Carbonyl α-Alkenylation.

2-Cyclopentenone derivatives have been efficiently synthesized from 5-bromo-5-hexen-2-ones via palladium-catalyzed intramolecular carbonyl α-alkenylation followed by double-bond migration under mild reaction conditions.

Rh(I) -Catalyzed Intramolecular Carbonylative C-H/C-I Coupling of 2-Iodobiphenyls Using Furfural as a Carbonyl Source.

Synthesis of fluoren-9-ones by a Rh-catalyzed intramolecular C-H/C-I carbonylative coupling of 2-iodobiphenyls using furfural as a carbonyl source is presented. The findings indicate that the rate-determining step is not a C-H bond cleavage but, rather, the oxidative addition of the C-I bond to a Rh(I) center.

ChemInform Abstract: Scope of Successive C—H Functionalizations of the Methyl Group in 3‐Picolines: Intramolecular Carbonylation of Arenes to the Metal‐Free Synthesis of 4‐Azafluorenones.

AbstractVarious 2‐aryl substituted 3‐picolines are efficiently transformed into 4‐azafluorenes and the products are isolated as single regioisomers.

ChemInform Abstract: Chemoselective Intramolecular Carbonyl Ylide Formation Through Electronically Differentiated Malonate Diesters.

AbstractTrapping of the carbonyl ylides by alkynes is examined, and depending on the ylides substituents either functionalized oxabicyclic compounds are produced in a chemo‐, regio‐ and diastereoselective manner or tetronic acids are obtained as mixtures of diastereomers.

ChemInform Abstract: Confined Acid‐Catalyzed Asymmetric Carbonyl—Ene Cyclization.

AbstractThis is the first organocatalytic asymmetric intramolecular carbonyl—ene reaction of olefinic aldehydes.

Scope of Successive C-H Functionalizations of the Methyl Group in 3-Picolines: Intramolecular Carbonylation of Arenes to the Metal-Free Synthesis of 4-Azafluorenones.

A transition-metal-free, t-BuOOH mediated intramolecular carbonylation of arenes in 2-aryl-3-picolines via oxidative C-H functionalizations of the methyl group has been developed, providing an expedient synthesis of 4-azafluorenones. Distinct from the current literature wherein methylarenes have been used as acylating agents, 2-aryl-3-picolines in this study are transformed into aldehydes, which give 4-azafluorenones upon rapid intramolecular acylation. The study demonstrates the first example of intramolecular carbonylation of arenes utilizing a methyl group as latent carbonyl functionality.

Chemoselective Intramolecular Carbonyl Ylide Formation through Electronically Differentiated Malonate Diesters.

A method for chemoselective carbonyl ylide formation utilizing the Rh(II) catalyzed decomposition of electronically differentiated diazo malonates is disclosed. Treatment of ethyl, trifluoro ethyl diazo malonate with a Rh(II) catalyst selectively forms a carbonyl ylide from the relatively electron rich ethyl ester. This carbonyl ylide can be trapped by various alkynes giving highly functionalized oxabicyclic compounds in a chemo-, regio-, and diastereoselective fashion.

ChemInform Abstract: Synthesis of Substituted Benzenes via Bi(OTf)3‐Mediated Intramolecular Carbonyl Allylation of α‐Prenyl or α‐Geranyl β‐Arylketosulfones.

Intramolecular carbonyl allylation of α-prenyl or α-geranyl β-arylketosulfones 5 in the presence of molecule sieves (MS) affords substituted benzenes 6–7 in moderate to good yields. The facile transformation proceeds by a synthetic sequence starting with the α-prenylation or α-geranylation of 1 and the Bi(OTf)3-mediated annulation of 5 followed by a sequential desulfonative aromatization or then an intramolecular Friedel–Crafts alkylation. A plausible mechanism has been studied and proposed.

Structure of a dinuclear cadmium complex with 2,2'-bi-pyridine, monodentate nitrate and 3-carb-oxy-6-methyl-pyridine-2-carboxyl-ate ligands: intra-molecular carbon-yl(lone pair)⋯π(ring) and nitrate(π)⋯π(ring) inter-actions.

The centrosymmetric dinuclear complex bis-(μ-3-carb-oxy-6-methyl-pyridine-2-carboxyl-ato)-κ(3) N,O (2):O (2);κ(3) O (2):N,O (2)-bis-[(2,2'-bi-pyridine-κ(2) N,N')(nitrato-κO)cadmium] methanol monosolvate, [Cd2(C8H6NO4)2(NO3)2(C10H8N2)2]·CH3OH, was isolated as colourless crystals from the reaction of Cd(NO3)2·4H2O, 6-methyl-pyridine-2,3-di-carb-oxy-lic acid (mepydcH2) and 2,2'-bi-pyridine in methanol. The asymmetric unit consists of a Cd(II) cation bound to a μ-κ(3) N,O (2):O (2)-mepydcH(-) anion, an N,N'-bidentate 2,2'-bi-pyridine group and an O-mono-dentate nitrate anion, and is completed with a methanol solvent mol-ecule at half-occupancy. The Cd complex unit is linked to its centrosymmetric image through a bridging mepydcH(-) carboxyl-ate O atom to complete the dinuclear complex mol-ecule. Despite a significant variation in the coordination angles, indicating a considerable departure from octa-hedral coordination geometry about the Cd(II) atom, the Cd-O and Cd-N distances in this complex are surprisingly similar. The crystal structure consists of O-H⋯O hydrogen-bonded chains parallel to a, further bound by C-H⋯O contacts along b to form planar two-dimensional arrays parallel to (001). The juxtaposed planes form inter-stitial columnar voids that are filled by the methanol solvent mol-ecules. These in turn inter-act with the complex mol-ecules to further stabilize the structure. A search in the literature showed that complexes with the mepydcH(-) ligand are rare and complexes reported previously with this ligand do not adopt the μ-κ(3) coordination mode found in the title compound.

Synthesis of Substituted Benzenes via Bi(OTf)3-Mediated Intramolecular Carbonyl Allylation of α-Prenyl or α-Geranyl β-Arylketosulfones.

Intramolecular carbonyl allylation of α-prenyl or α-geranyl β-arylketosulfones 5 in the presence of molecule sieves (MS) affords substituted benzenes 6-7 in moderate to good yields. The facile transformation proceeds by a synthetic sequence starting with the α-prenylation or α-geranylation of 1 and the Bi(OTf)3-mediated annulation of 5 followed by a sequential desulfonative aromatization or then an intramolecular Friedel-Crafts alkylation. A plausible mechanism has been studied and proposed.

The first carbamoyl–carboxylate complex of transition metals: Synthesis and structure of {(OC4H8NH)[OC4H8NC([dbnd]O)]Pd}2(μ-CMe3CO2)2

Reactions of palladium(I) carbonyl carboxylate complexes [Pd(μ-CO)(μ-RCO2)]n with secondary amines on the example of morpholine were studied. It was found that intramolecular carbonylation of amine in coordination sphere of polynuclear palladium species proceeds and binuclear palladium carbamoyl complex {(OC4H8NH)[OC4H8NC(O)]Pd}2(μ-RCO2)2 forms as a result. This is the first structurally characterized carbamoyl–carboxylate complex of transition metals. Also it was shown that morpholine itself and carboxylate-anions act as proton acceptors in the reaction of carbonylation of morpholine by coordinated CO.

ChemInform Abstract: Synthesis of a Common Cyclopentanoid Building Block for the Total Synthesis of Jatropha‐5,12‐ and ‐6(17),11‐dienes by Uncatalyzed Intramolecular Carbonyl Ene (ICE) Reaction.

AbstractKey intermediates (I) and (II) serve as building blocks for attempted syntheses of euphoheliosnoid D (III) and euphodendoridin D (IV).

1.2.5. Synthesis, crystal structure and catalytic activity of 2-methoxycarbonylethyldichlorotin hydroxide

Abstract: 2-methoxycarbonylethyldichlorotin hydroxide, CH 3 OCOCH 2 CH 2 SnCl 2 (OH) ( 1), has been synthesized by hydrolysis reaction and characterized by elemental analysis, FTIR, 1 H NMR spectroscopy, and X-ray single crystal diffraction. Compound 1 is a centrosymmetric dimmer, and the tin atom approximates to octahedral geometry via an intramolecular carbonyl- to-tin coordination and hydroxo-bridging. The compound display high selectivity and good catalysis activity on the transesterification reaction of ethyl acetoacetate with an alcohol. Supporting information: FT-IR, 1 H NMR, X-Ray, GC/MS analyses, Cif file.

ChemInform Abstract: Cyclopentanoids by Uncatalyzed Intramolecular Carbonyl Ene (ICE) Reaction of α‐Keto Esters.

ChemInform Abstract: Cyclopentanoids by Uncatalyzed Intramolecular Carbonyl Ene (ICE) Reaction of α‐Keto Esters.

Catalytic intramolecular carbonyl–ene reaction with ketones: evidence for a retro–ene process

The ene and reverse ene-processes occur with ketones, as shown by control experiments and by ESI-MS analysis.

Tandem gold self-relay catalysis for the synthesis of 2,3-dihydropyridin-4(1 H)-ones: combination of σ and π Lewis acid properties of gold salts.

The dual ability of gold salts to act as π- and σ Lewis acids has been exploited in a tandem self-relay catalysis. Thus, triphenylphosphanegold(I) triflate mediated the intramolecular carbonyl addition of the amide functionality of homoprogargyl amides to a triple bond. The formation of a σ complex of the gold salt with the intermediate oxazine promoted a nucleophilic addition followed by a Petasis-Ferrier rearrangement. This tandem protocol, catalyzed by the same gold salt under the same reaction conditions, gave rise to the efficient synthesis of 2,3-dihydropyridin-4-(1 H)-ones, which contain a cyclic quaternary α-amino acid unit. The asymmetric version was performed by generating the starting materials from the corresponding sulfinylimines.

Synthesis of a Common Cyclopentanoid Building Block for the Total Synthesis of Jatropha-5,12- and -6(17),11-dienes by Uncatalyzed Intramolecular Carbonyl­ Ene (ICE) Reaction

We report the scalable synthesis of a common cyclopentanoid building block for 15-hydroxyjatropha-5,12- and -6(17),11-dienes in 11 steps. Key to the synthesis is an uncatalyzed intramolecular carbonyl ene (ICE) reaction of an e,ζ-unsaturated α-keto ester.

Cyclopentanoids by uncatalyzed intramolecular carbonyl ene (ICE) reaction of α-keto esters.

The uncatalyzed intramolecular carbonyl ene (ICE) reaction of substituted ε,ζ-unsaturated α-keto esters to terpenoid-related building blocks has been studied. We found a beneficial effect of a silyl substituent at the ene segment on the kinetics of the ICE reaction. A generalizable and scalable synthesis of ε,ζ-unsaturated α-keto esters from allylic alcohols was developed.

Highly stereoselective synthesis of cyclopentanes bearing four stereocentres by a rhodium carbene-initiated domino sequence.

Stereoselective synthesis of a cyclopentane nucleus by convergent annulations constitutes a significant challenge for synthetic chemists. Though a number of biologically relevant cyclopentane natural products are known, more often than not, the cyclopentane core is assembled in a stepwise fashion due to lack of efficient annulation strategies. Herein, we report the rhodium-catalyzed reactions of vinyldiazoacetates with (E)-1,3-disubstituted 2-butenols generate cyclopentanes, containing four new stereogenic centers with very high levels of stereoselectivity (99% ee, >97 : 3 dr). The reaction proceeds by a carbene–initiated domino sequence consisting of five distinct steps: rhodium–bound oxonium ylide formation, [2,3]-sigmatropic rearrangement, oxy-Cope rearrangement, enol–keto tautomerization, and finally an intramolecular carbonyl ene reaction. A systematic study is presented detailing how to control chirality transfer in each of the four stereo-defining steps of the cascade, consummating in the development of a highly stereoselective process.