Total Syntheses of (±)-Gephyrotoxin and (±)-Perhydrogephyrotoxin

This article describes the full details of our total syntheses of gephyrotoxin and perhydrogephyrotoxin. Our central strategy toward the total synthesis is based on the use of an N-methoxy group as a reactivity control element. The N-methoxyamide group enabled unique transformations, involving i) the direct coupling reaction of the N-methoxyamide with an aldehyde, and ii) the amide-selective reductive allylation. These reactions were never accomplished without the assistance of the N-methoxy group. The amide-selective reductive allylation of the N-methoxyamide was especially practical, and excluded a number of extra steps including protecting group manipulations and redox reactions in the total syntheses.