Stereoselective Synthesis of C3-C12 Dihydropyran Portion of Antitumor Laulimalide Using Copper-Catalyzed Oxonium Ylide Formation-[2,3] Shift
作者:Takayuki Yakura、Wataru Muramatsu、Jun'ichi Uenishi
DOI:10.1248/cpb.53.989
日期:——
Copper-catalyzed oxonium ylide formation–[2,3] shift of (5S,7R)-5-allyloxy-1-diazo-8-(p-methoxybenzyloxy)-7-methyl-2-octanone (3) proceeded in tetrahydrofuran-dichloromethane (4 : 1) under reflux with an excellent stereoselectivity (97 : 3) to give (2R,6S)-2-allyl-6-[(2R)-3-(p-methoxybenzyloxy)-2-methylpropyl]-3-dihydropyranone (2) as a major isomer in 82% yield. The resultant pyranone (2) was converted to the key intermediate (1) of the Mulzer's laulimalide synthesis and its derivatives (14, 15).
铜催化的氧鎓叶立德形成——(5S,7R)-5-烯丙氧基-1-重氮-8-(对甲氧基苄氧基)-7-甲基-2-辛酮(3)的[2,3]转移在四氢呋喃中进行-二氯甲烷(4:1)回流,具有优异的立体选择性(97:3),得到(2R,6S)-2-烯丙基-6-[(2R)-3-(对甲氧基苄氧基)-2-甲基丙基]-3 -二氢吡喃酮(2)作为主要异构体,产率82%。所得吡喃酮 (2) 转化为 Mulzer 月桂酰亚胺合成的关键中间体 (1) 及其衍生物 (14, 15)。