Sulphone-mediated cyclobutanone to α-alkoxy-cyclopentanone ring expansion reactions; scope, limitations and applications
作者:Harry Finch、Adnan M.M. Mjalli、John G. Montana、Stanley M. Roberts、Richard J.K. Taylor
DOI:10.1016/s0040-4020(01)85603-9
日期:1990.1
treated with the lithiated sulphone (4) to give the ring expanded α-methoxyketones (12), (14) and (16) generally as a mixture of epimers. The same bicycloalkanones furnished the α-benzyloxyketones (13), (15), and (17) on reaction with reagent (5). The ketone (3) reacted with the sulphone anion (6) to give, after Lewis acid treatment, the α-allyloxycyclopentanone derivatives (27a) and (27b) and one of
用锂化的砜(4)处理双环烷酮(1)-(3),得到一般为差向异构体混合物的扩环α-甲氧基酮(12),(14)和(16)。在与试剂(5)反应时,相同的双环烷酮提供了α-苄氧基酮(13),(15)和(17)。酮(3)与砜阴离子(6)反应,经路易斯酸处理后,得到α-烯丙氧基环戊酮衍生物(27a)和(27b),其中一种化合物(27b)被转化为醚(31)。将双环庚酮(20)转化为四个环扩产物(22a),(22b),(24a)和(24b),并使用一种化合物(24a)合成前列环素类似物(36)。简要研究了路易斯酸催化的中间体羟基砜重排成扩环化合物的机理。