On the formation of allenes in the steroid series IV. Synthesis and structure of several 3-methoxy-19-nor-1,3,5(10)-17(20), 20-pregnapentaenes, substituted at C(21)
作者:L.A. van Dijck、B.J. Lankwerden、J.C.G.M. Vermeer
DOI:10.1002/recl.19790981202
日期:——
Pairs of steroid 17(20),20-allenes, epimeric at C(21), have been obtained by LiAlH4(D4)/AlCl3 reduction of 17α/β-hydroxy-17β/α-alkynyl steroids, confirmed by means of optical rotation differences and NMR spectroscopy. In all cases the reduction proved to be fully stereospecific, confirming the cis-SN2′ mechanism, postulated in part II1.
通过LiAlH 4(D 4)/ AlCl 3还原17α/β-羟基-17β/α-炔基类固醇获得了成对的类固醇17(20),20-丙二烯,在C(21)对映体旋光差异和NMR光谱分析。在所有情况下,还原均被证明是完全立体定向的,从而证实了顺式S N 2'机制,这在第二部分1中有假设。