DL-A-nor-estr-3(5)-ene-2,17-dione is regio- and stereospecifically synthesized from 1-acetal-protected 7a-methyl-2,3,5,6,7,7a-hexa- hydroindene-1,5-dione in five steps in ca. 23% overall yield. The key step is the regiospecific trapping of an enolate of the dione with 6,6-(1,2-ethanediyldioxy)-2-trimethylsilyl-3-oxo-1-heptene.
DL-A-nor-雌-3(5)-烯-2,17-二酮是通过特定区域和立体选择性地从1-
乙缩醛保护的7a-甲基-2,3,5,6,7,7a-六氢
茚-1,5-二酮经五步合成得到的,总收率约为23%。关键步骤是使用6,6-(1,2-乙二氧基)-2-三甲基
硅基-3-氧代-
1-庚烯对二酮的烯醇盐进行区域选择性捕获。