Ring-closing olefin metathesis for the synthesis of 1,8-diazabicyclo[4.3.0]non-3-ene-7,9-diones
摘要:
A novel method for the efficient synthesis of 1,8-diazabicyclo[4.3.0]non-3-ene-7,9-diones 5 (bicyclic hydantoins) starting from ureas or Z-protected aminoacids has been developed. The key step is a ring-closing metathesis (RCM) reaction of diallyl substituted hydantoins 3 catalyzed by the ruthenium-carbene complex bis(tricyclohexylphosphine)benzilidine ruthenium dichloride (4). (C) 1997 Elsevier Science Ltd.