描述了标题化合物2的全合成,标题化合物2是孕酮去氧孕烯和3-酮去氧孕烯的潜在前体。类固醇的骨架是通过1,2-二氢-4,7-二甲氧基萘(12)和[ S-(Z)]-8,9-二羟基-7-乙基-6-壬烯-2-炔基的缩合而组装的。由[ R -(+)]-甘油醛丙酮化物(4)制备的丙烯酸甲酯9-(叔丁基二甲基)甲硅烷基醚(11),然后进行克莱森重排。将所得的二类甾类固醇(14)在170°C加热,得到9,11-类固醇类固醇15和16的1:1混合物分别具有8α,13β,14α-和8α,13α,14α构型。将13β-受体15转化为与三苯膦反应的11-溴-13-乙基-3-甲氧基-9,11-焦酮-1,3,5(10)-三烯-9,17-二酮(21)。在高压条件下(12 kbar,55°C)得到相应的phospho盐22。22的分子内Wittig反应在C-8处进行差向异构化,仅得到(8α)-13-乙基-3-甲氧基gona-1
Intramolecular [3 + 2]cycloadditions: synthesis of 1-methylene-2,3,3a,4,5,9b-hexahydro-1H-benz[e]indenes and an unsuccessful approach to ergot alkaloids
作者:Michael P. Collins、Michael G. B. Drew、John Mann、Harry Finch
DOI:10.1039/p19920003211
日期:——
3-enyl)-4-methoxybenzenes, prepared by a short synthesis, underwent intramolecular [3 + 2]cycloadditions to produce the title indenes. An analogous intramolecularcycloaddition was attempted with N-benzyl-4-(2-methoxyvinyl)-3-(2-hydroxy-3-trimethylsilylmethylbut-3-enyl)indoline, in an attempt to produce a key intermediate for ergot alkaloid synthesis, but this was unsuccessful.
Diastereocontrol via the phenol- and palladium(II)-catalyzed Claisen rearrangement with cyclic enol ethers
作者:Kōichi Mikami、Kazuhiko Takahashi、Takeshi Nakai
DOI:10.1016/s0040-4039(01)81079-0
日期:1987.1
Taking the judicious choice of either 2,6-dimethylphenol or PdCl2(RCN)2 as the catalyst, the Claisen rearrangements with the enol ethers of cyclic ketones are shown to proceed with a high level of either anti or syn diastereoselection, respectively.
Total synthesis of naturally occurring spirobisnaphthalene palmarumycin CP17 and its methoxy analogues was first achieved through Friedel-Crafts acylation, Wolff-Kishner reduction, intramolecular cyclization, ketalization, benzylic oxidation, and demethylation using the inexpensive and readily available methoxybenzene, 1,2-dimethoxybenzene and 1,4-dimethoxybenzene and 1,8-dihydroxynaphthalene as raw