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

摘要

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 1-substituted derivatives.