Addition of Organometallic Compounds to Tin-Containing Cyclic Ketones. Remote Stereocontrol Induced by the Stannyl Group
作者:Asunción Barbero、Francisco J. Pulido、Juan A. Rincón
DOI:10.1021/ja036340c
日期:2003.10.1
(Z)-beta-Stannylvinyl ketones (Sn/CO separation: 5 bonds) react with organolithium reagents, showing a high degree of stereocontrol. On the contrary, the analogous ketones with E stereochemistry do not show selectivity at all. In the case of beta-stannyl ketones (Sn/CO separation: 3 bonds), the long distance between the tin center and the carbonyl group does not favor selective addition except when allyllithium
syn to tin is the preferred mode of addition of organolithium reagents to the carbonyl group of cyclic ketones with a β-stannylvinyl group. This remarkable remote control is a consequence of the anchoring of the organolithium reagent by the tin and carbonyl groups.