Copper-Catalyzed Regioselective and Diastereoselective Synthesis of Borylated 1-Benzo[ <i>b</i> ]azepines

Abstract

A practical regioselective and diastereoselective synthesis of functionalized 1-benzo[ b]azepines by copper-catalyzed intramolecular cyclization has been developed. The reaction involves borylcupration of a mixture of ( E/ Z)-1,3-dienes, followed by capture of the generated ( Z)-allylcopper species with an imine to produce 7-membered N-heterocycles as single diastereomers. The reaction is applicable to various ( E/ Z)-dienyl arenes with an imine moiety at the ortho-position, including aryl, alkyl, and heterocyclic aldimines, and ketimines, affording borylated 2,3- cis-substituted 1-benzo[ b]azepines in good yields.