Synthesis of the taxol AB-system by olefination of an A-ring C1 ketone and direct B-ring closure
作者:David Crich、Swaminathan Natarajan、Joyce Z Crich
DOI:10.1016/s0040-4020(97)00411-0
日期:1997.5
Two syntheses of 13-deoxy-taxol C1 ketones are presented. Olefination of these C1 ketones is achieved, indirectly, via either the Meyer-Schuster reaction or by introduction of a vinyl group with vinylcerium dichloride followed by allylic rearrangement. Both methods provide the E-olefin exclusively. Dihydroxylation of these olefins is achieved with catalytic OsO4 and NMNO in moderate yield, providing
介绍了13-脱氧紫杉醇C1酮的两种合成方法。通过Meyer-Schuster反应或通过用二氯化乙烯基铈引入乙烯基,然后进行烯丙基重排,间接实现这些C1酮的烯烃化。两种方法仅提供E-烯烃。这些烯烃的二羟基化反应可通过催化的OsO 4和NMNO以中等收率实现,从而为紫杉醇-1,2-二醇单元提供正确的相对立体化学。通过在C9处将α-磺酰基阴离子置换为C9处的烯丙基溴,可以以极好的收率实现B环的封闭。