Uncatalyzed conjugate addition of organozinc halides to enones in DME: a combined experimental/computational study on the role of the solvent and the reaction mechanism
calculations, prompted by the experimental aggregation study, revealed an unexpected reactionmechanism, where the coordinating capabilities of DME stabilize a transition state involving two organozinc moieties, lowering the activation energy of the reaction with respect to that seen for THF, enough to explain the fast and quantitative reactions observed experimentally and the different behaviors of
Effect of InCl 3 on the addition of Grignard reagents to α,β-unsaturated carbonyl compounds
作者:Brian G. Kelly、Declan G. Gilheany
DOI:10.1016/s0040-4039(01)02263-8
日期:2002.1
Control of 1,2- versus 1,4-addition of organometallic reagents to enones remains a long-standing problem. There is still no satisfactory 1,2-directing agent comparable to the 1,4-directing effect of copper salts. We report that the presence of just 5 mol% indium(III) chloride can significantly alter the amount of 1,2-product formed in these reactions.
The conjugateaddition of organolithium reagent to α, β-unsaturatedketone has been accomplished with methylaluminum bis(2, 6-di-tert-butyl-4-alkylphenoxide) (MAD and MAT). Here combination of alkyllithium and MAD (or MAT) constitutes an amphiphilic system that allows to exhibit unusual selectivity in the alkylation of enones with alkyllithium.
Amphiphilic reactions by means of exceptionally bulky organoaluminum reagents. Rational approach for obtaining unusual equatorial, anti-Cram, and 1,4 selectivity in carbonyl alkylation