Total synthesis of (–)-carbovir

Optically pure (–)-carbovir has been prepared by two different routes involving stereospecific opening of chiral cyclopentene epoxides by substituted purines. Introduction of the 2′,3′ unsaturation was accomplished by mesylate elimination, either after introduction of the purine (Route 1), or earlier in the sequence, producing a novel vinyl epoxide (Route 2).