New approaches toward the synthesis of (D-homo) steroid skeletons using Mukaiyama reactions
作者:Florence C.E. Sarabèr、Alexander Baranovsky、Ben J.M. Jansen、Maarten A. Posthumus、Aede de Groot
DOI:10.1016/j.tet.2005.11.056
日期:2006.2
Mukaiyama reaction between the silyl enol ether of 6-methoxytetralone and 2-methyl-2-cyclopentenone or carvone, with transfer of the silyl group to the receiving enone, gave a second silyl enol ether. Addition of a carbocation, generated under Lewis acid conditions from 3-methoxy-2-butenol, 3-ethoxy-3-phenyl-2-propenol or 3-methoxy-2-propenol to this second silyl enol ether gave adducts, which could not
已经开发了用于合成类固醇和D-均质类固醇骨架的新的,简短而灵活的程序。在6-甲氧基四氢萘酮的甲硅烷基烯醇醚和2-甲基-2-环戊烯酮或香芹酮之间的Mukaiyama反应,将甲硅烷基基团转移到接收的烯酮上,得到第二种甲硅烷基烯醇醚。在路易斯酸条件下,由3-甲氧基-2-丁烯醇,3-乙氧基-3-苯基-2-丙烯醇或3-甲氧基-2-丙烯醇生成的碳正离子加成到第二种甲硅烷基烯醇醚中,不能得到加合物。通过醛醇缩合环化成(D-均质)类固醇骨架而被环化。6-甲氧基四氢萘酮的甲硅烷基烯醇醚与2-甲基-2-Cylopentenone的Mukaiyama-Michael反应产生了第二种甲硅烷基烯醇醚,后者与3-羟基-3-(4-甲氧基苯基)生成的碳正离子高收率反应丙烯。该加合物中双键的臭氧分解得到三羰基化合物(Zieglers triketone),该化合物已用于合成9,11-脱氢雌酮甲基醚。通过添加由ZnBr生成的