A simple, user-friendly process for the homologation of aldehydes using tosylhydrazone salts

Aldehydes can be homologated to ketones in moderate to good yields using aryldiazomethanes generated in situ from tosylhydrazones. Chiral aldehydes can be employed with almost complete retention of configuration. The tosylhydrazones can also be generated in situ from the corresponding aldehyde leading to a one-pot process for coupling two different carbonyl compounds to give ketones. (C) 2000 Elsevier Science Ltd. All rights reserved.