Diastereoselective Tandem Michael−Intramolecular Wittig Reactions of a Cyclic Phosphonium Ylide with 8-Phenylmenthyl Enoates
作者:Tomoko Nagao、Takanori Suenaga、Takao Ichihashi、Tetsuya Fujimoto、Iwao Yamamoto、Akikazu Kakehi、Ryozo Iriye
DOI:10.1021/jo001379a
日期:2001.2.1
diastereoselectivity of the initial tandem reactions was estimated to be 94:6 from the 31P NMR of a mixture of the diastereomeric ketal derivatives 6a and 6'a which were obtained by the reaction of 5a with (2R,3R)-2,3-butanediol, and the absolute configuration of the major isomer was determined by the single-crystal X-ray analysis. Similar reactions using some 8-phenylmenthyl alkenoates were attempted. As a result
研究了使用8-苯基薄荷基烯酸酯的五元环状phospho叶立德2的非对映选择性串联Michael-分子内Wittig反应。磷鎓叶立德与肉桂酸8-苯基薄荷基酯反应,然后水解得到的烯醇醚4a,得到(3R,4S)-4-(二苯基膦基)-3-苯基环庚酮(3R,4S)-5a作为主要异构体。从通过5a与(2R,3R)-2,3-反应获得的非对映体缩酮衍生物6a和6'a的混合物的31P NMR估算,初始串联反应的非对映选择性为94:6。丁二醇和主要异构体的绝对构型由单晶X射线分析确定。尝试使用一些8-苯基薄荷基链烯酸酯进行类似的反应。结果是,