Conjugate addition of O-silylatedketeneacetals to α,β-unsaturated carbonyl compounds in acetonitrile gave quantitative yields of the corresponding β-(alkoxycarbonyl)methyl O-silyl enolates . Site specific electrophilic substitutions of yielded the corresponding α-substituted β-(alkoxycarbonyl)-methylalkanones , , and .
Carbon-carbon bond formation catalyzed by lithium perchlorate in dichloromethane
作者:Manfred T. Reetz、David N.A. Fox
DOI:10.1016/s0040-4039(00)77505-8
日期:1993.2
perchlorate suspended in dichloromethane provides a mild and effective medium for Mukaiyama aldol reactions of aldehydes with silyl keteneacetal (1). 2-Cyclohexenone undergoes clean 1,4-addition under similar conditions. Catalyst activity is much higher in dichloromethane than in diethylether.
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.
Highly effective catalysts for the conjugate addition of silyl ketene acetals to enones (Mukaiyama-Michael reaction)
作者:Valérie Berl、Günter Helmchen、Stephanie Preston
DOI:10.1016/s0040-4039(00)76519-1
日期:1994.1
Conjugate additions of O-silylated acetals to simple enones have been reported to proceed without a catalyst if acetonitrile is used as solvent. Inability to repeat this procedure led to the discovery that an as yet unknown species formed from P4O10 in acetonitrile displays high catalytic activity.
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.