Employment of a cyclobutene ring-opening metathesis reaction towards a concise synthesis of (±)-sporochnol A

A concise formal synthesis of (+/-)-sporochnol A 1, a naturally occurring feeding deterrent towards herbivorous fish, is described. The target compound was prepared by the employment of a Ru-catalysed cyclobutene ring-opening metathesis reaction with gaseous ethylene followed by a site selective hydroboration reaction as the key steps. The optimisation of the metathesis process regarding the Ru-catalyst and reaction conditions is also delineated. (C) 2001 Elsevier Science Ltd. All rights reserved.