Metal‐Free Alkenylation of Salicylaldehydes with Boronic Acids: Synthesis of Skipped Dienes and 2<i>H</i>‐Chromenes

Abstract

Metal‐free alkenylation of salicylaldehydes and the preparation of 2 H ‐chromenes have been developed. Reactions occur in the presence of tetrafluoroboric acid diethyl ether complex. Vinylboronic acid derivatives including indeneboronic acid react readily with salicylaldehydes to afford the corresponding skipped dienes. When 6‐bromo or 6‐chlorosalicylaldehydes are submitted to the reaction conditions the formation of 2 H ‐chromenes is observed in good to excellent yields.