Molecules, Vol. 28, Pages 1401: Catalyst-Free Formal Conjugate Addition/Aldol or Mannich Multicomponent Reactions of Mixed Aliphatic Organozinc Reagents, π-Electrophiles and Michael Acceptors
Molecules doi: 10.3390/molecules28031401
Authors: Marine Pinaud Marc Presset Erwan Le Gall
Catalyst-free multicomponent reactions of mixed alkylzinc reagents with Michael acceptors and aldehydes, ketones or activated imines are described. Primary, secondary and tertiary alkylzinc reagents, pre-generated in acetonitrile from the corresponding iodoalkanes, were used in the process, leading to the very efficient formation of a variety of β-hydroxycarbonyl compounds. The imines showed more contrasting results, due to the direct addition of the organozinc compound to the C=N bond. Mechanistic assays involving TEMPO account for a polar instead of a radical character of the reaction.