A new preparation of 2,5-dihydro-1-benzoxepins using Mitsunobu cyclization, and the synthesis of natural radulanins

Mitsunobu cyclization of o-[4-hydroxy-3-methyl-2(Z)-butenyl]pheno 2a effected selective seven-membered cyclization to give 3-methyl-2,5-dihydro-1-benoxepin la. Using this procedure, natural radulanin A and radulanin A methyl ether were synthesized effectively. (C) 2000 Elsevier Science Ltd. All rights reserved.