method of silyl dienol ethers via 1,4-Brook rearrangement–Wittig reaction sequence has been developed. This tandem reaction proceeded via the intramolecular silyl migration step, which enabled stereoselective formation of phosphorane intermediates. The reaction is operationally simple and high yielding, thus providing a new useful formula for silyl dienol ether synthesis.
Stereoselective Synthesis of (<i>Z</i>)- and (<i>E</i>)-Allylic Silanes by Copper-Mediated Substitution Reactions of Allylic Carbamates with Grignard Reagents
作者:Jacqueline H. Smitrovich、K. A. Woerpel
DOI:10.1021/jo991312r
日期:2000.3.1
Both (Z)- and (E)-allylic silanes were prepared with high stereoselectivity by the copper-mediated substitution of allylic carbamates by organometallic reagents. The reaction of alkylmagnesium reagents with (E)-allylic carbamates provides (Z)-allylic silanes, whereas both alkylmagnesium and alkyllithium reagents react with (Z)-allylic carbamates to afford (E)-allylic silanes. Because Grignard reagents