Electrochemical Synthesis and Chemistry of Chiral 1-Cyanotetrahydroisoquinolines. An Approach to the Asymmetric Syntheses of the Alkaloid (−)-Crispine A and Its Natural (+)-Antipode
(90:10 dr) and (−)-11 (85:15 dr) were prepared from the alkylation–reduction sequence of a common α-amino nitrile (+)-4 derivative that has been conveniently prepared by anodic cyanation. Elaboration of the pyrrolidine ring of the title compound was cleanly achieved by two efficient ring closures methods involving (a) the displacement of a halogen atom and (b) the formation of a cyclic iminium cation to
Acid promoted cyclodehydration of amino alcohols with amide acetal
作者:Soonho Hwang、Heemin Park、Yongseok Kwon、Sanghee Kim
DOI:10.1039/c4ra10625c
日期:——
A convenient acid-promoted cyclization protocol for the formation of azaheterocycles from amino alcohols is described. The reaction involves the use of N,N-dimethylacetamide dimethyl acetal (DMADA) as the activating reagent of the hydroxyl group. Using this protocol, pyrrolidines or piperidines with various substituents can be synthesized in good to high yields.