Alkynyliodonium salts in organic synthesis. Development of a unified strategy for the syntheses of (-)-agelastatin A and (-)-agelastatin B

The total syntheses of natural agelastatin A and agelastatin B were accomplished via a strategy that utilized an alkynyliodonium. salt --> alkylidenecarbene --> cyclopentene transformation to convert a relatively simple amino alcohol derivative to the functionalized core of the agelastatin system. Subsequent manipulations delivered debromoagelastatin, which served as a precursor to both agelastatin A and agelastatin B. Alkylidenecarbene insertion chemoselectivity issues were explored en route to the final targets.