Propargyl-type alcohols (6) and the corresponding esters of carbonic acid (4) or acetic acid (5) react with two equivalents of Me2PhSiH in the presence of catalytic amounts of Rh4(CO)12 under CO pressure at 100°C to give 2-(dimethylphenylsilylmethyl)-2-alkenals (3), whereas 2-substituted-3-(dimethylphenylsilyl)propenals (7, 8 and 9) are also isolated with the concomitant formation of 3 when a similar reaction is operated with shortage of Me2PhSiH or with lowering of reaction temperature. The isolated 9 is selectively converted to 3 by the Rh4(CO)12 catalyzed reaction with Me2PhSiH under CO pressure. This fact suggests that the transformation of 4, 5 or 6 to 3 is accomplished by either a one-pot procedure or a stepwise procedure relayed by 7, 8 or 9. Usefulness of this protocol is demonstrated by the synthesis of 18 in which ethisterone (17) is directly converted by a one-pot procedure.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry