Stereoselective Organocatalytic Approach to α,β-Disubstituted-β-amino Acids: A Short Enantioselective Synthesis of Cispentacin
作者:Ana Pou、Albert Moyano
DOI:10.1002/ejoc.201300197
日期:2013.5
α-Branched α,β-unsaturated aldehydes have been tested in the organocatalytic tandem Michael addition/cyclization with N-(benzyloxycarbonyl)hydroxylamine, a reaction which until now has been restricted to α-unsubstituted enals. Starting from cyclopentene-2-carbaldehyde, and using diphenylprolinol trimethylsilyl ether as a chiral amine catalyst, this approach has led to the development of a practical
α-支链 α,β-不饱和醛已在有机催化串联迈克尔加成/与 N-(苄氧羰基)羟胺的环化中进行了测试,该反应迄今为止仅限于 α-未取代的烯醛。以环戊烯-2-甲醛为原料,并使用二苯基脯氨醇三甲基甲硅烷基醚作为手性胺催化剂,该方法开发了一种实用的、高产率(93-98% 总产率,三步)和高对映选择性(高达98:2 er) 环状 β-氨基酸顺喷菌素的路线,与之前描述的这种生物活性天然产物的不对称合成相比具有优势。当使用无环 α-支链 α,β-不饱和醛作为底物时,反应产率取决于醛的取代模式,并获得顺式和反式异构体的混合物。