Catalytic Synthesis of Phthalide Derivatives via Asymmetric Bromolactonization of Stilbene‐type Carboxylic Acids usingN,N‐Dibenzyl Diaminomethylenemalononitrile as Organocatalyst

Abstract

AbstractThe asymmetric 5‐exobromolactonization of stilbene‐type carboxylic acids could be achieved using aN,N‐dibenzyl diaminomethylenemalononitrile organocatalyst with high yields and excellent enantioselectivities (up to 92% ee) of the corresponding phthalide derivatives. This is the first report where the successful synthesis of the phthalide derivatives as the main product, with high optical purity, could be achieved using the asymmetric 5‐exobromolactonization of the stilbene‐type carboxylic acids with various substituents.