C-1 Reactivity of 2,3-Epoxy Alcohols via Oxirane Opening with Metal Halides: Applications and Synthesis of Naturally Occurring 2,3-Octanediol, Muricatacin, 3-Octanol, and 4-Dodecanolide

The C-1 reactivity of 2,3-epoxy alcohols and derivatives has been examined thoroughly. In the first approach a rearrangement opening of 2,3-epoxy alcohols with LiI leads to 1-iodo 2,3-diols with erythro or three stereochemistry starting from trans or cis epoxy alcohols. Subsequent coupling with a carbon nucleophile can lead to a series of vicinal diols with predicted relative and absolute stereochemistry: the described methodology has been applied to the asymmetric synthesis of the naturally occurring (S,S)-2,3-octanediol and (R,R)-muricatacin. The second approach, starting from easily available tosyloxy epoxides, leads to the highly regioselective opening of the oxirane ring with Li halides. The 3-iodohydrins obtained can be reduced to the corresponding 1-(tosyloxy)alkan-2-ols and then coupled with common carbon nucleophiles to afford, in high yields, optically active alcohols. This methodology has been applied to the asymmetric synthesis of naturally occurring pheromones like 3(R)-octanol and 4(R)-dodecanolide.