Asymmetric hydrogenation of dibenzo-fused azepines with chiral cationic ruthenium diamine catalysts

Abstract

Highly efficient asymmetric hydrogenation of dibenzo[b,f][1,4]oxazepine, dibenzo[b,f][1,4]thiazepine and dibenzo[b,e]azepine derivatives with chiral cationic ruthenium diamine catalysts has been developed, giving diverse chiral seven-membered N-heterocycles with excellent results (up to 99% yield and 99% ee). Moreover, it was found that the catalyst counteranion regulated the enantioselectivity obviously in the hydrogenation of dibenzo[b,f][1,4]thiazepine and dibenzo[b,e]azepine derivatives.