Reduction of 5-substituted 5,8a-trans-oxazolo[3,4-a]pyridin-8-ones (7a,b), obtained by an application of α-acylamino radical cyclization at the initial stage, with NaBH4 and K-Selectride was found to proceed with complete stereocontrol in all cases. Reduction of 1-substituted 1,8a-trans-oxazolo[3,4-a]pyridin-8-one (7c) and pyrrolidine analogue (10) with NaBH4 and K-Selectride was also found to proceed with high diastereoselectivity. © 1990.