Deoxygenation reaction of steroidal 16, 17-ketols 1, 2 and 6 as well as their silyl ethers 3 and 7 and 16- and 17-iodoketone analogs 11, 12, and 14 with trimethylsilyl iodide (TMSI) or HI under various conditions was examined. The results indicate that the deoxygenation producing 16- and 17-ketones 9 and 8 proceeds through multiple reaction pathways; a direct iodination of a siloxy group of the ketol silyl ethers by iodide ion to give the iodoketones (path b), addition of TMSI to a carbonyl group of the ketol silyl ethers to yield diiodo derivatives 22 and 23 through iodo-bis-TMS compounds 20 and 21 (path a), and cleavage of ether bond of dimers 15-18 initially produced are, at least, involved. In these sequences, rearrangement of the 16-ketols 1 and 2 to the 17β-ketol 6 also plays a significant role. The yields of the ketones 9 and 8 and their relative amounts would be dependent on the relative importance of each pathway in the reaction.
研究了甾族16、17-酮醇1、2和6及其甲
硅烷基醚3和7以及16-和17-
碘酮类似物11、12和14与三甲基
碘硅烷(TMSI)或HI在各种条件下的脱氧反应。结果表明,脱氧生成16-和17-酮9和8是通过多种反应途径进行的;通过
碘离子直接
碘化酮醇甲
硅烷基醚的甲
硅烷氧基,得到
碘酮(路径b),将TMSI加成到酮醇甲
硅烷基醚的羰基上,通过
碘-双-TMS化合物生成二
碘代衍
生物22和23 20和21(路径a),并且至少涉及最初产生的二聚体15-18的醚键的断裂。在这些序列中,16-酮醇 1 和 2 重排为 17β-酮醇 6 也发挥着重要作用。酮9和8的产率及其相对量将取决于反应中每个途径的相对重要性。