Catalytic Asymmetric Approach to 1,3,4,5‐Tetrahydro‐1,4‐benzodiazepin‐2‐ones in One‐Pot

Abstract

AbstractHerein we illustrate a first asymmetric synthesis of medicinally attractive tetrahydro‐1,4‐benzodiazepin‐2‐ones performed under catalytic conditions and one‐pot fashion. The process relies on a sequential Knoevenagel reaction/asymmetric epoxidation/domino ring‐opening cyclization (DROC) using commercially available aldehydes, phenylsulfonylacetonitrile, cumyl hydroperoxide, 2‐(aminomethyl)aniline and a readily available quinine‐derived urea as the catalyst. The heterocycles have been isolated with good regioselectivity, satisfactory to good yield and up to 98 % ee. The protocol proved also to be suitable for the preparation of previously undescribed 1,5‐dihydro‐4,1‐benzoxazepin‐3(2H)‐ones with up to 86 % ee.