Diastereospecific ring cleavage of bornane-2,3-dione in the Bucherer-Bergs reaction

A novel regio- and diastereospecific ring cleavage of bornane-2,3-dione (camphor quinone) under Bucherer-Bergs reaction conditions has been investigated. The simplicity of this transformation provides a novel and straightforward synthetic pathway to enantiopure derivatives of cyclopentane carboxylic acid as well as functionalized hydantoins in just two steps, starting from inexpensive and easily available camphor.

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(1R,3S)-3-[(4R)-2,5-Dioxoimidazolidin-4-yl]-1,2,2-trimethylcyclopentanecarboxamideC12H19N3O3de = 100%[α]D28=+156.0 (c 0.50, DMSO)Source of chirality: (R)-(+)-camphorquinoneAbsolute configuration: (1R,3S,4R)