Biogenetically inspired synthesis and skeletal diversification of indole alkaloids
作者:Haruki Mizoguchi、Hideaki Oikawa、Hiroki Oguri
DOI:10.1038/nchem.1798
日期:2014.1
occurring alkaloids. Three distinct modes of [4+2] cyclizations and two types of redox-mediated annulations provided divergent access to five skeletally distinct scaffolds involving iboga-, aspidosperma-, andranginine- and ngouniensine-type skeletons and a non-natural variant within six to nine steps from tryptamine. The efficiency of our approach was demonstrated by successful total syntheses of (±)-vincadifformine
We report the first asymmetric Diels–Alderreactionbetween furan and propiolates. Propiolate, a dienophile, was equipped with an Evans’ auxiliary and a sulfonyl group to control and facilitate diastereoselective cycloaddition. Treatment with furan as a diene and aluminium Lewis acid afforded a 7-oxabicyclo[2.2.1]heptadiene skeleton diastereoselectively. The origin of diastereoselectivity can be explained