Syntheses of cyclopentyl nucleoside (−)-neplanocin A through tetrazole-fragmentation from cyanophosphates

Abstract

Abstact We recently reported a novel synthetic method for five-membered unsaturated cyclic compounds from ketones involving cyanophosphates (CPs) under neutral conditions, in which alkylidene carbenes generated through tetrazole-fragmentation undergo [1,5]-C H insertions to produce the target compounds. The present paper describes the use of the tetrazole-fragmentation from CPs for the efficient and practical syntheses of (−)-neplanocin A and a protected tetrol, the latter of which is an important synthetic precursor of both (−)-neplanocin A and its analogues. Furthermore, formation of an unusual dihydropyran derivative was observed during the synthetic study of the tetrol.