Mild, Metal-Free Oxidative Ring-Expansion Approach for the Synthesis of Benzo[ b]azepines.

Benzo[ b]azepines are important structural motifs for the pharmaceutical industry. However, their syntheses are usually lengthy, involving several steps, transition-metal catalysts, and/or harsh conditions. A novel, general, mild, and metal-free oxidative ring expansion tandem reaction of hydroquinolines with TMSCHN2 as a versatile soft nucleophile to gain access to these valuable compounds in a simple and straightforward manner is presented.