作者:James R. Bull、Michiel C. Loedolff
DOI:10.1039/p19960001269
日期:——
Conjugate alkylation of 3-methoxyestra-1,3,5(10),15-tetraen-17-one 1 leads to 15β-alkyl 17-ketones 2 (Me, Et or Pri), which are converted, via palladium acetate-mediated dehydrosilylation of their derived silyl enol ethers, into the corresponding 15-alkyl Δ15-17-ketones 5. Conjugate alkylation of these intermediates results in formation of 15,15-dialkyl 17-ketones 10, which undergo stereoselective reduction with lithium aluminium hydride, and deprotection of C-3 to give 15,15-dialkyl analogues 12 of estradiol. Spectroscopic data are presented to demonstrate that substrates 1 and 5 undergo exclusive 15β-alkylation.
3-methoxyestra-1,3,5(10),15-tetraen-17-one 1 的共轭烷基化生成 15β-烷基 17-酮 2(Me、Et 或 Pri),并通过乙酸钯介导进行转化将其衍生的甲硅烷基烯醇醚脱氢硅烷化成相应的15-烷基Δ15-17-酮5。这些中间体的共轭烷基化导致形成15,15-二烷基17-酮10,其与氢化铝锂进行立体选择性还原,并且C-3脱保护得到雌二醇的15,15-二烷基类似物12。光谱数据证明底物 1 和 5 发生排他性 15β-烷基化。