Asymmetric Michael Additions via 6- and 7-Membered Lactone SAMP-Hydrazones: Diastereo- and Enantioselective Synthesis of Substituted Lactone Esters
作者:Dieter Enders、Pascal Teschner、Robert Gröbner、Gerhard Raabe
DOI:10.1055/s-1999-3397
日期:1999.2
Lactone esters (S/R,S)-5a-f were synthesized in good overall yields (37-61%, two steps) and diastereo- and enantiomeric excesses (de = 88-≥96%, ee = 81 -≥96%) by 1,4-addition of metalated lactone-SAMP-hydrazones (S)-2 to enoate Michael acceptors 3 and subsequent oxidative cleavage of the product hydrazones by ozonolysis. The relative and absolute configuration was determined by X-ray structure analysis of (R,S)-5c.
通过将金属化的内酯-SAMP-酰肼 (S)-2 与烯酸酯迈克尔受体 3 进行 1,4 加成,并随后通过臭氧裂解氧化裂解产物酰肼,合成了内酯(S/R,S)-5a-f,总产率(37-61%,两步法)和非对映过量(de = 88-≥96%,ee = 81-≥96%)均良好。(R,S)-5c 的相对和绝对构型是通过 X 射线结构分析确定的。