Urea/Transition-Metal Cooperative Catalyst for anti-Selective Asymmetric Nitroaldol Reactions
作者:Kai Lang、Jongwoo Park、Sukwon Hong
DOI:10.1002/anie.201107785
日期:2012.2.13
A cooperativecatalyst that features urea H‐bonding and a cobalt center was developed for anti‐selective asymmetric Henry reactions (see scheme). The H‐bonds of urea play a crucial role in the improvement in yield (from 30 % to 84 %), enantioselectivity (from 78 % to 96 %), and anti diastereoselectivity (from 3:1 to 48:1). A short synthesis of (1R,2S)‐methoxamine hydrochloride was also accomplished
An easily available N,N′-dioxide/Cu(I) complex has been developed for the catalyticasymmetric nitroaldol (Henry) reaction of aldehydes with nitroethane. Under mild reaction conditions, a series of substituted aromatic, heteroaromatic and α,β-unsaturated aldehydes are transformed to the corresponding anti-β-nitroalcohols in good to excellent yields (up to 99%) with moderate to good dr (up to 16.7:1
已开发出一种易于获得的N,N'-二氧化物/ Cu(I)络合物,用于醛与硝基乙烷的催化不对称硝基醛醇(Henry)反应。下温和的反应条件下,一系列的取代的芳族,杂芳族和α,β -不饱和醛转化为相应的抗-β-硝基醇以良好至优异的产率(高达99%)的中度至良好博士(高达1670: 1 anti / syn)和高ee值(高达97%)。除硝基乙烷外,还使用硝基甲烷和1-硝基丙烷作为亲核试剂,并获得了良好的对映选择性。