Spirocyclization strategy toward indole phytoalexins. The first synthesis of (±)-1-methoxyspirobrassinin, (±)-1-methoxyspirobrassinol, and (±)-1-methoxyspirobrassinol methyl ether

The first syntheses of cruciferous indole phytoalexins (+/-)-1-methoxyspirobrassinin, (+/-)-1-methoxyspirobrassinol, (+/-)-1-methoxyspirobrassinol methyl ether as well as a new syntheses of phytoalexins (+/-)-spirobrassinin and cyclobrassinin were achieved by dioxane dibromide (DDB)-mediated spirocyclization of brassinin and its I-substituted derivatives. (C) 2002 Elsevier Science Ltd. All rights reserved.