Diastereoselective Synthesis of 2,6-Disubstituted 3-Hydroxypiperidine, 2-(a-Hydroxyalkyl)-3-hydroxypiperidine and 2-(a-Hydroxyalkyl)-3-hydroxypyrrolidine Derivatives

Abstract
Reduction of 5-substituted 5,8a-trans-oxazolo[3,4-a]pyridin-8-ones (7a,b), obtained by an application of .alpha.-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-transoxazolo[3,4-a]pyridin-8-one (7c) and pyrrolidine analogue (10) with NaBH4 and K-Selectride was also found to proceed with high diastereoselectivity.
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