Synthesis of 2,3-disubstituted pyrrolidines by intramolecular addition of α-aminoalkyl radicals to electron deficient C C bonds
摘要:
2,3-Disubstituted pyrrolidines are prepared by SmI2-pranoted cyclization of alpha-amino radicals generated from N-(alpha-benzotriazolylalkyl)alkenylamines containing a C=C bond activated by an electron withdrawing substituent. The diastereoselectivity of cyclization is moderate and depends on the nature of the substituent at the pyrrolidine 2-position. (C) 1999 Elsevier Science Ltd. All rights reserved.
Abstract Two different organocatalytic approaches for the asymmetricsynthesis of 2,3,4-trisubstituted piperidines were developed. Both approaches were based on an aza-Michael addition followed by cyclization and gave products in high enantiomeric excess. Two different organocatalytic approaches for the asymmetricsynthesis of 2,3,4-trisubstituted piperidines were developed. Both approaches were based
Streamlined Synthesis of C(sp<sup>3</sup>)-Rich <i>N</i>-Heterospirocycles Enabled by Visible-Light-Mediated Photocatalysis
作者:Nils J. Flodén、Aaron Trowbridge、Darren Willcox、Scarlett M. Walton、Yongjoon Kim、Matthew J. Gaunt
DOI:10.1021/jacs.9b03372
日期:2019.5.29
We report a general visible-light-mediated strategy that enables the construction of complex C(sp3)-rich N-heterospirocycles from feedstock aliphatic ketones and aldehydes with a broad selection of alkene-containing secondary amines. Key to the success of this approach was the utilization of a highly reducing Ir-photocatalyst and orchestration of the intrinsic reactivities of 1,4-cyclohexadiene and
An intramolecular Michael reaction of 9 stereoselectively gave the tricyclic compound (10), which was converted to (±)-protoemetinol (2) and 13. Compound 13 is an important intermediate for the synthesis of (±)-emetine. A simpler preparation of 13 was also carried out by the intramolecular Michael reaction of 14, followed by reduction of the ketone moietv. Furthermore, the stereoselective formation of 26, which is an intermediate for the synthesis of (±)-emetine, was achieved by the floowing sequence of reactions : intramolecular Michael reaction, of the ketone moiety, and removal of the N-carbomethoxy group.
A Concise Approach to 2-Azabicyclo[3.3.1]nonane Derivatives from an Acyclic Precursor
作者:José M. Aurrecoechea、José M. Gorgojo、Carlos Saornil
DOI:10.1021/jo051471c
日期:2005.11.1
5-amino-2-alkenoate ester with α-unsubstituted aliphatic aldehydes leads to substituted 1,2,3,4-tetrahydropyridines. Subsequent manipulation of the ester and enamine functions gives a quick access to 2-azabicyclo[3.3.1]nonane-containing compounds.