Suzuki-type cross-coupling reaction of 3-iodoindazoles with aryl boronic acids: a general and flexible route to 3-arylindazoles

This paper describes a Suzuki Type cross coupling reaction of 3-iodoindazoles with aryl and heteroaryl boronic acids as a general route to 3-arylindazoles. The coupling reaction is illustrated by the preparation of new aryl- or heteroarylindazoles 7. Scope and limitation of the method are outlined. The coupling reaction works best on a 1-substituted indazole nucleus. The usefulness of the reaction is illustrated by a short practical synthesis of YC-1, a pharmacological agent potentialy useful for the treatment of cardiovascular diseases or erectile dysfunction. (C) 1999 Elsevier Science Ltd. All rights reserved.