Highly enantioselective conjugate addition of 1-bromonitroalkanes to α,β-unsaturated ketones catalyzed by 9-amino-9-deoxyepiquinine
作者:Li-ting Dong、Rui-jiong Lu、Quan-sheng Du、Jun-min Zhang、Sheng-ping Liu、Yi-ning Xuan、Ming Yan
DOI:10.1016/j.tet.2009.03.055
日期:2009.5
Asymmetric conjugate addition of 1-bromonitroalkanes to α,β-unsaturated ketones was studied using chiral primary amines as the catalysts. 9-Amino-9-deoxyepiquinine was found to be highly efficient catalyst for the transformation. 4-Bromo-4-nitroketones were obtained with excellent enantioselectivities (97–99% ee) and good yields (61–99%) for a variety of alkyl vinyl ketones. The product could be further
以手性伯胺为催化剂,研究了1-溴硝基烷烃向α,β-不饱和酮的不对称共轭加成反应。发现9-氨基-9-脱氧表醌是转化的高效催化剂。获得的4-溴-4-硝基酮具有出色的对映选择性(97-99%ee)和良好的收率(61-99%),适用于各种烷基乙烯基酮。该产物可以进一步用Bu 3 SnH / AIBN脱溴,以提供高收率的手性4-硝基酮,而没有光学纯度的损失。