Synthesis of aromatic steroids by palladium(0) coupling and electrocyclic ring closure
作者:Thomas L. Gilchrist、Richard J. Summersell
DOI:10.1039/p19880002603
日期:——
by an acid-catalysed 1,2 methyl shift. The corresponding cyclopentenol (1d) has been prepared from the bromonaphthalene (6) and 3-(t-butyldimethylsilyloxy)-1-iodocylopentene (7) by palladium(0)-catalysed cross coupling. This cyclises in bromobenzene to give the cyclopentaphenanthrene (5b) and the alcohols (3d) and (3e). The known estrone intermediate (9) has been prepared by oxidation of these alcohols
用硼氢化钠将萘基环戊烯酮(1a)还原为醇(1c)。当在二甲苯中加热时,它会环化,得到estra-1,3,5(10),8(14),9(11)-pentaen-17-ols(2)。17α-醇(2a)是混合物的主要成分,是纯净的分离产物。当在戊苯中加热环戊醇(1c)时,产物为estra-1,3,5(10),8,14-pentaen-17-ols(3b)和(3c),以及碳氢化合物17 -甲基环戊[ a ]菲(5a)。该化合物可能是由醇(2)或(3)由酸催化的1,2-甲基转移。相应的环戊烯醇(1d)已经通过钯(0)催化的交叉偶联由溴萘(6)和3-(叔丁基二甲基甲硅烷氧基)-1-碘二十二碳戊烯(7)制备。这在溴苯中环化,得到环戊菲(5b)和醇(3d)和(3e)。已知的雌酮中间体(9)已经通过这些醇的氧化制备。