Asymmetric synthesis of all-carbon benzylic quaternary stereocenters via conjugate addition to alkylidene and indenylidene Meldrum's acids.
A systematic study outlining the enantioselective 1,4-addition of dialkylzinc reagents to 5-(1-arylalkylidene) and indenylidene Meldrum's acids is presented. Variation of the aryl and alkyl groups present on the alkylidene was thoroughly explored. The 1,4-addition displayed compatibility with a wide range of heteroaromatics and functional groups, and the arene pattern of substitution affected enantioselection, with a para-substituted aryl group consistently leading to high enantioselectivities. The nature of the organozinc reagent on the efficiency and selectivity of the conjugate addition was also investigated. The solid-state conformation was determined for a number of alkylidene Meldrum's acids and correlated with the observed enantioselectivity in relation to the arene pattern of substitution.
Wilsily
Ashraf
A
Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Fillion
Eric
E
D001593:Benzyl Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D004146:Dioxanes / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D001593:Benzyl Compounds; D004146:Dioxanes; D007659:Ketones; C076489:Meldrum's acid