Synthesis of α-diazo-β-hydroxyesters through a one-pot protocol by phase-transfer catalysis:: application to enantioselective aldol-type reaction and diastereoselective synthesis of α-amino-β-hydroxyester derivatives

The one-pot synthesis of alpha-diazo-beta-hydroxyesters from sodium azide under phase-transfer-catalyzed conditions has been achieved. This protocol includes three different chemical transformations promoted by a single catalyst in each step to give products in good to excellent yields. The reaction was applied to a catalytic asymmetric aldol-type reaction Using alpha-diazoesters with aldehydes in the presence of a chiral quaternary ammonium salt and gave products with up to 81% ee. The diastereoselective transformation of the products to chiral alpha-amino-beta-hydroxyester derivatives is also described. (c) 2005 Elsevier Ltd. All rights reserved.