Bis(oxazoline) Lewis Acid Catalyzed Aldol Reactions of PyridineN-Oxide Aldehydes—Synthesis of Optically Active 2-(1-Hydroxyalkyl)pyridine Derivatives: Development, Scope, and Total Synthesis of an Indolizine Alkaloid
作者:Aitor Landa、Anna Minkkilä、Gonzalo Blay、Karl Anker Jørgensen
DOI:10.1002/chem.200501475
日期:2006.4.24
A new, short, and simplified procedure for the synthesis of optically active pyridine derivatives from pro-chiral pyridine-N-oxides is presented. The catalytic and asymmetric Mukaiyama aldol reaction between ketene silyl acetals and 1-oxypyridine-2-carbaldehyde derivatives catalyzed by chiral copper(II)-bis(oxazoline) complexes gave optically active 2-(hydroxyalkyl)- and 2-(anti-1,2-dihydroxyalkyl)pyridine
提出了一种新的,短而简化的从前手性吡啶-N-氧化物合成旋光吡啶衍生物的方法。烯酮甲硅烷基缩醛与手性铜(II)-双(恶唑啉)配合物催化的1-氧吡啶-2-甲醛反应之间的催化和不对称的Mukaiyama羟醛反应,得到旋光的2-(羟烷基)-和2-(反-1, 2-二羟基烷基)吡啶衍生物,具有良好的收率和非对映选择性,并具有优异的对映选择性,最高达99%对映体过量。作为所开发方法的合成应用,提供了非天然吲哚嗪生物碱的不对称全部合成的完整说明。