Cascade cyclization, dipolar cycloaddition of azomethine imines for the synthesis of pyrazolidines
作者:Hélène D. S. Guerrand、Harry Adams、Iain Coldham
DOI:10.1039/c1ob06122d
日期:——
one-pot reaction of aldehydes with hydrazines has been used for the preparation of tetrahydropyrazoles and dihydropyrazoles. The chemistry involves condensation then cyclization, followed by inter- or intramolecular dipolar cycloaddition of the resulting azomethine imine intermediates. The intramolecular cycloaddition gives fused tricyclic compounds as single diastereoisomers. The intermolecular cycloaddition
Stereoselective Formation of Fused Tricyclic Amines from Acyclic Aldehydes by a Cascade Process Involving Condensation, Cyclization, and Dipolar Cycloaddition
作者:Adam J. M. Burrell、Iain Coldham、Luke Watson、Niall Oram、Christopher D. Pilgram、Nathaniel G. Martin
DOI:10.1021/jo8019913
日期:2009.3.20
halide or dipolarophile has been studied. Several primary amines including simple amino acids such as glycine, alanine, and phenylalanine and derivatives such as glycine ethyl ester and also hydroxylamine have been investigated. High yields are obtained in the formation of different tricyclic ring sizes; the dipolar cycloaddition necessarily creates a five-membered ring, and we have investigated the formation