A CONVENIENT METHOD FOR THE SYNTHESIS OF α, β-UNSATURATED CARBONYL COMPOUNDS
作者:Teruaki Mukaiyama、Tadashi Ohsumi
DOI:10.1246/cl.1983.875
日期:1983.6.5
A variety of α,β-unsaturated ketones are conveniently synthesized from enaminoketones and organolithium compounds especially when the reaction is carried out in petroleum ether; this reaction provides a facile method for the synthesis of α,β,γ-trisubstituted 2-cyclopentenones in combination with the regioselective alkylation of enaminoketones.
A process for preparing an optically active ketone represented by formula (I): ##STR1## wherein R.sup.1 represents a hydrogen atom or an alkyl group having from 1 to 5 carbon atoms; and n represents 1 or 2, which comprises asymmetrically hydrogenating an .alpha., .beta.-unsaturated ketone represented by formula (II): ##STR2## wherein R.sup.1 and n are as defined above, in the presence of a ruthenium-optically active phosphine complex as a catalyst. An optically active ketone having a high optical purity can be prepared.
substrates having a bulky substituent, such as a tert-Bu group, at the beta-position give high yields. Bulkiness is also required in cyclic alpha,beta-unsaturated ketones, but the effect is small. In alkyl vinyl ketones, the reactivity decreased with the steric bulk of the alkyl group. In aryl vinyl ketones, the presence of an electron-donating group on the aromatic ring decreases the reactivity. The