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[Figure not available: see fulltext.] A simple and convenient approach to the synthesis of N-substituted 1,3-oxazolidines via a hetero-domino Petasis borono-Mannich reaction of 1,2-amino alcohols, formaldehyde, and organoboronic acids has been reported. T

Azomethine ylides are fascinating 1,3-dipoles for [3 + 2] cycloaddition reactions toward the construction ofN-heterocycles. Herein, an efficient and environmentally benign electrochemical approach for the generation of a nonstabilized azomethine ylide has been established under metal-free and external oxidant-free conditions. The resulting 1,3-dipole undergoes a [3 + 2] cycloaddition reaction with olefins. This electrosynthetic methodology indulges a straightforward and facile approach for the construction of substituted pyrrolidines.

A methodology for the synthesis of 7,12-dihydro-5H-6,12-methanodibenzo[c,f]azocines from aromatic aldehydes and N-(methoxymethyl)-N-(trimethylsilylmethyl)benzylamine using catalysis by trifluoroacetic and perchloric acids is described. The developed protocol was applied for the synthesis of N-unsubstituted and N-methyl-4-aryltetrahydroisoquinolines.

A mild and reproducible method for the formation of a nonstabilized azomethine ylide was developed by photoinduced reaction catalyzed with eosin Y under green light irradiation. Resulting 1,3-dipole was trapped with fluoroalkenes, fluoroalkylated alkenes,

A mild and reproducible method for the formation of a nonstabilized azomethine ylide was developed by photoinduced reaction catalyzed with eosin Y under green light irradiation. Resulting 1,3-dipole was trapped with fluoroalkenes, fluoroalkylated alkenes,

The 1,3-dipolar cycloaddition reaction of a non-stabilized azomethine ylide 4a, formed in situ from N-(methoxymethyl)-N-(trimethylsilylmethyl)benzylamine 5 and a catalytic amount of trifluoroacetic acid, with aromatic aldehydes 3 gives rise to N-benzyl-5-

Thermolysis of oxazolidines leads to azomethine ylids via cycloreversion.In the liquid phase, these intermediates then give 1-3 dipolar cycloaddition; in the gaseous phase, they lead to aziridines.With an alkyl group in position 2, we observed also the formation of enamines.The effect of substituents on both the cycloreversion reaction and the evolution of azomethine ylids was studied.The mechanism of the process tautomerism aziridine -> azomethine ylid -> enamine is discussed.Keywords - azomethine ylids / oxazolidines / cycloreversion / aziridines / enamines / tautomerism

α-Phenylthio substituted amines have been found to be convenient reagents for the preparation of the pyrrolidine ring.Benzylamine (2) undergoes 1,3-dipolar cycloaddition with several dipolarophiles in the presence of silver fluoride.The reaction is believed to proceed via the intermediacy of an azomethine ylide.Treatment of α-(phenylthio)cyanoamines 10 and 17 with strong base results in the loss of the phenylthio group, and formation of substituted trans-piperazines 21, 22 in the case of 17.The mechanism of the reaction involves dimerization of the initially formed cyano substituted azomethine ylide intermediate, which behaves as a captodative diradical.Finally, the reaction of several alkenylamines with tributyltin hydride was studied as a method for generating the pyrrolidine ring via a radical cyclization reaction.

A series of α-cyanoaminosilanes has been found to act as azomethine ylide equivalents. Treatment of these compounds with silver fluoride in the presence of electron deficient olefins gives substituted pyrrolidines in high yield. The extent ofdiastereoselectivity associated with the 1,3-dipolar cycloaddition of chiral azomethine ylides with several dipolarophiles has been studied. Reasonable levels of such diastereoselectivity have been found when optically active α-cyanoaminosilanes are employed as azomethine ylide equivalents. These compounds can be prepared in multigram quantities by treating the appropriate chiral amine with chlorotrimethylsilane followed by reaction of the resulting secondary amine with formaldehyde in the presence of potassium cyanide. It was found that N-benzyl-N-cyanomethyl-N-trimethylsilylmethylamine undergoes stereospecific cycloaddition with dimethyl fumarate and maleate. The stereospecificity of the reaction is consistent with a concerted cycloaddition reaction.