1,3-Dipolar cycloadditions of azomethine ylides to alkenylboronic esters. Access to substituted boron analogues of β-proline and 3-hydroxypyrrolidines
摘要:
3-Boronic esters-substituted pyrrolidines were prepared via 1,3-dipolar cycloadditions of azomethine ylides to alkenyl boronates. Hydrolysis gave boron analogues of substituted beta-prolines, while treatment with trimethylamine oxide afforded the corresponding pyrrolidin-3-ols. (C) 2004 Elsevier Ltd. All rights reserved.
Chiral boronates—versatile reagents in asymmetric synthesis
作者:Sabine Thormeier、Bertrand Carboni、Dieter E Kaufmann
DOI:10.1016/s0022-328x(02)01323-2
日期:2002.9
The new, axially chiral borates 2, 9, and 11 and boronates 3–6 and 12 are synthesized in good yields. They are representatives of three different structural types. The bicyclic borates 2 and 9 are homochiral propeller compounds; their exclusive formation is used to increase the enantiomerical purity of 1. Especially the borates are efficient Lewis acidic catalysts for stereoselective Diels–Alder reactions