Stereoselective Construction of Halogenated Quaternary Stereogenic Centers via Catalytic Asymmetric Diels−Alder Reaction
作者:Kazutaka Shibatomi、Kentaro Futatsugi、Fumito Kobayashi、Seiji Iwasa、Hisashi Yamamoto
DOI:10.1021/ja1018628
日期:2010.4.28
brominated cis-fused bicyclic adduct derived from 2-bromocyclopenten-1-one and Dane's diene was converted to the trans-fused bicyclic system via reductive alkylation with the bulky aluminum reagent aluminum tris(2,6-diphenylphenoxide) (ATPH). With this process, formal syntheses of (+)-estrone and norgestrel have been demonstrated.
描述了 α-卤代-α、β-不饱和酮与路易斯酸活化手性 oxazaborolidine 1 的高度对映选择性 Diels-Alder 反应。与 α-氟代烯酮的反应提供了相应的环己烷衍生物,其具有高达 99% de 和 94% ee 的氟化季立体中心。与 α-溴环烯酮的反应提供了相应的溴双环加合物,其 de 含量高达 99%,ee 含量高达 95%。衍生自 2-bromocyclopenten-1-one 和 Dane's 二烯的溴化顺式稠合双环加合物通过使用笨重的铝试剂铝三(2,6-二苯酚)(ATPH)进行还原烷基化转化为反式稠合双环系统。通过这个过程,已经证明了 (+)-雌酮和炔诺孕酮的正式合成。