Lithiated camphor-derived oxazolidinone SN-acetals as chiral formyl anion synthons in additions to aldehydes.: Asymmetric synthesis of α-hydroxy aldehydes and α-hydroxy acids

N-(Phenylthiomethyl)oxazolidinones derived from camphor can be lithiated and added to aldehydes in good yields and stereoselectivities. The adducts are crystalline, which simplifies isolation of the major diastereomer from the product mixture. Hydrolysis affords enantiopure alpha-hydroxy aldehydes, which can be oxidized to alpha-hydroxy acids in good yields. The steric course of the reaction is analyzed in detail and a mechanistic model is presented. (C) 2002 Elsevier Science Ltd. All rights reserved.