Scandium-Catalyzed Allylboration of Aldehydes as a Practical Method for Highly Diastereo- and Enantioselective Construction of Homoallylic Alcohols
作者:Hugo Lachance、Xiaosong Lu、Michel Gravel、Dennis G. Hall
DOI:10.1021/ja036807j
日期:2003.8.1
A general approach for the allylation of aldehydes using stable, air-tolerant camphor-based chiralallylboronates under Sc(OTf)3 catalysis is described. This practical methodology provides both syn and anti propionate units and other homoallylic alcohols with very high levels of diastereo- and enantioselectivity for several substrates, including functionalized aliphatic aldehydes useful toward the
Synthetic studies toward the pyran core and the amide side chain of psymberin
作者:Hugo Lachance、Olivier Marion、Dennis G. Hall
DOI:10.1016/j.tetlet.2008.07.170
日期:2008.10
A synthetic approach to the polysubstituted pyran core and amide side chain of psymberin (irciniastatin A) using stereoselective organoboron methodology is described. An advanced oxyranyl pyran intermediate was prepared using a catalytic enantioselective and diastereoselective three-component reaction involving first an inverse electron-demand hetero [4+2] cycloaddition between 3-boronoacrolein pinacolate and 1-ethoxy-2-methylpropene, followed by an allylboration of ethyl glyoxylate. The amide side chain was prepared highly efficiently using the first example of a doubly diastereoselective allylboration of a chiral alpha-alkoxy aldehyde under the Lewis acid-catalyzed reaction manifold. (C) 2008 Elsevier Ltd. All rights reserved.