Efficient and stereoselective one-pot synthesis of benzoboxazolo3,4-d1,4oxazin-1-ones

摘要

An efficient and mild one-pot convergent synthesis protocol has been developed for benzoboxazolo3,4-d1,4oxazin-1-one derivatives through the Mitsunobu reaction and sequential cyclization. Various tricyclic fused benzoxazinyl-oxazolidinones (20 examples) were obtained in good to excellent yields and high enantioselectivities with facile operation. Furthermore, four stereoisomers were afforded respectively in high ee values (>97.8)viausing different chiral 2,3-epoxy-4-trityloxybutanol. This methodology has been applied to the synthesis of key intermediates of drug candidates.