these reactions. Enhanced preference for the more sterically demanding Michael adducts is obtained with Bu(2)Sn(OTf)(2), SnCl(4), and Et(3)SiClO(4) in the former reaction while TiCl(4) gives the highest selectivity for the less sterically demanding products in the latter case. These results are interpreted in terms of alternative reaction mechanisms. The reaction of less bulky ketene silyl acetals are
Lithium perchlorate catalyzed conjugate addition of o-silylated ketene acetals to hindered α,β-unsaturated carbonyl compounds at atmospheric pressure
作者:Paul A. Grieco、R.J. Cooke、Kenneth J. Henry、James M. VanderRoest
DOI:10.1016/s0040-4039(00)92276-7
日期:1991.1
O-Silylated ketene acetals undergo 1,4 conjugate addition to hindered α,β-unsaturated carbonyl systems at atmospheric pressure in the presence of lithium perchlorate.
DuBay William J., Grieco Paul A., Todd Lee J., J. Org. Chem, 59 (1994) N 23, S 6898-6899
作者:DuBay William J., Grieco Paul A., Todd Lee J.
DOI:——
日期:——
Lithium Cobalt-Bis-Dicarbollide: A Novel Lewis Acid Catalyst for the Conjugate Addition of Silyl Ketene Acetals to Hindered .alpha.,.beta.-Unsaturated Carbonyl Compounds
作者:William J. DuBay、Paul A. Grieco、Lee J. Todd
DOI:10.1021/jo00102a009
日期:1994.11
The novel Lewis acid, lithium cobalt-bis-dicarbollide (1), in which the lithium ion is weakly coordinated to the Co(B9C2H11)(2)(1-)anion, is an effective, soluble catalyst for Mukaiyama-Michael reactions.