Facile synthesis of 2-vinylindolines via a phosphine-mediated α-umpolung/Wittig olefination/cyclization cascade process.

A novel phosphine-mediated α-umpolung/Wittig olefination/cyclization cascade process between o -aminobenzaldehydes and Morita-Baylis-Hillman (MBH) carbonates has been ingeniously developed. This protocol serves as a practical tool for the facile synthesis of a broad range of 2-vinylindolines in moderate to good yields under mild reaction conditions. The applicability of this method was demonstrated with gram-scale reaction and various transformations of the corresponding product.