Diastereoselective Synthesis of β-Substituted-α,γ-Diaminobutyric Acids and Pyrrolidines Containing Multichiral Centers
作者:Yan Huang、Qiong Li、Tian-Liang Liu、Peng-Fei Xu
DOI:10.1021/jo8023076
日期:2009.2.6
Configuration of the second new stereocenter was decided by the substitution of nitroalkene. Selective reduction and hydrolysis of the Michael adducts furnished the desired β-substituted-α,γ-diaminobutyric acids in good yields and high enantiomeric excesses (>99% ee). Synthesis of pyrrolidines containing multichiral centers has also been accomplished in good to excellent yields and diastereoselectivities
已经开发出一种方便高效的方法,用于高度非对映选择性合成含多手性中心的β-取代-α,γ-二氨基丁酸和吡咯烷。手性三环亚氨基内酯1和2的迈克尔加成当使用异丙醇钛(IV)时,生成硝基链烷烃可得到高收率(高达95%)和优异的非对映选择性(高达dr> 99:1)的加合物。第二个新的立体中心的构型由硝基烯烃的取代决定。迈克尔加合物的选择性还原和水解以良好的收率和高的对映体过量(> 99%ee)提供了所需的β-取代的-α,γ-二氨基丁酸。通过使用Cu(OTf)2或AgOTf作为脂肪族硝基烯烃的活化剂,通过Michael-Mannich串联反应,在温和条件下,还可以良好的收率和非对映选择性完成具有多手性中心的吡咯烷的合成。