Combining palladium and ammonium halide catalysts for Morita-Baylis-Hillman carbonates of methyl vinyl ketone: from 1,4-carbodipoles to ion pairs.

ABSTRACT: Here we report that Morita-Baylis-Hillman carbonates from diverse aldehydes and methyl vinyl ketones can be directly utilised as palladium-trimethylenemethane 1,4-carbodipole-type precursors, and both reactivity and enantioselectivity are finely regulated by adding a chiral ammonium halide as the ion-pair catalyst. The newly assembled intermediates, proposed to contain an electronically neutral π-allylpalladium halide complex and a reactive compact ion pair, efficiently undergo asymmetric [4 + 2] annulations with diverse activated alkenes or isatins, generally with high regio-, diastereo- and enantio-selectivity, and even switchable regiodivergent or diastereodivergent annulations can be well realised by tuning the substrate or catalyst assemblies. An array of control experiments, includin

SUBMITTER: Yang Y 

PROVIDER: S-EPMC8447884 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature