Stereoselective formation and rearrangement of morpholinium ylides derived from copper carbenoids
作者:Kevin W. Glaeske、B.N. Naidu、F.G. West
DOI:10.1016/s0957-4166(03)00095-8
日期:2003.4
Amino diazoacetoacetates 4a–e and 7a,b were prepared from readily available amino alcohols and subjected to copper-catalyzed carbene-transfer reaction. Substrates 4c–e furnished the morpholin-2-ones 5c–e in good yield via the corresponding cyclic ammonium ylides, albeit with poor diastereoselectivity. Substrates 4a,b failed to provide the corresponding morpholinones, perhaps as a result of steric congestion
氨基重氮乙酰乙酸酯4a – e和7a,b由容易获得的氨基醇制备,并进行铜催化的卡宾转移反应。尽管非对映选择性差,但底物4c – e通过相应的环状铵盐以高收率提供了吗啉-2-酮5c – e。底物4a,b可能不能提供相应的吗啉酮,这可能是由于空间拥挤的结果。环状底物7a,b经历转化为双环吗啉酮8和9收率高,非对映选择性中等。通过控制中间双环烷基化物的瞬时立体异构的铵中心,可以合理化该结果。