Nucleophilic eliminative ring fission of bridgehead substituted 1,3-bishomocubyl acetates
作者:A.J.H. Klunder、W.C.G.M. de Valk、J.M.J. Verlaak、J.W.M. Schellekens、J.H. Noordik、V. Parthasarathi、B. Zwanenburg
DOI:10.1016/s0040-4020(01)96416-6
日期:1985.1
regio- and stereospecifically to the thermodynamically favored half cage ketones 22,28 and 31, respectively. In contrast, the cage opening of the β-ketoacetates 5 and 15 is essentially directed by the β-ketone function. In the case of 5, regiospecific cleavage of the central C4-C5 bond is observed producing in a stereospecific manner diketone 25 in quantitative yield. Under similar conditions, acetate
描述了三种不同类型的官能化桥头取代的1,3-双同丁二酸乙酸酯(即A,B和C)的碱基诱导的笼裂变。两种6-官能化的1,3-双同型4-乙酸酯(A型),即4-乙酰氧基五环[5.3.0.0 2,5 .0 3,9 .0 4,8 ] decan-6-one 5的合成及其从容易获得的Diels-Alder加合物4开始已经完成了乙缩醛6。合成3种1,3-双同型8-乙酸8酯(B型),即8-乙酰氧基五环[5.3.0 2,5 .0 3,90.0 4,8 ]癸烷-6-酮15,其乙烯缩醛16和父醋酸20已经执行了从所述环戊二烯-苯醌的加合物开始7。的碱诱导homoketonization 6,16和20的引线区域选择性和立体有择的热力学有利的半笼酮22,28和31分别。相反,β-酮乙酸酯5和15的笼子开口基本上由β-酮官能团控制。在5的情况下,中央C 4 -C 5的区域特异性裂解观察到以立体特异性方式以定量产率产生