A Study on the Allylic Substitution of (1R,5R,8R)- and (1R,5R,8S)-8-Hydroxy-2-oxabicyclo[3.3.0]oct-6-en-3-one Derivatives − Preparation of (1S,2R,3R)-9-[2-Hydroxy-3-(2-hydroxyethyl)cyclopent-4-en-1-yl]-9H-adenine
both C-6 and C-8 substituted products, thus limiting the synthetic use of the reaction with these nucleophiles. Additionally, Mitsunobu substitution of (1R,5R,8R)-8-hydroxy-2-oxabicyclo[3.3.0]oct-6-en-3-one (3) with 6-chloropurine, followed by reduction of the lactone moiety and treatment with liquid ammonia, gave the carbocyclic nucleoside (1S,2R,3R)-9-[2-hydroxy-3-(2-hydroxyethyl)cyclopent-4-en-1-yl]-9H-adenine