Large-Scale Synthesis of Singh’s Catalyst in a One-Pot Procedure Starting from Proline

• DOI: 10.1021/op200283q
• Publication Date: 2011-12-01T17:49:14Z
• Authors: Albrecht Berkessel; Wacharee Harnying; Nongnaphat Duangdee; Jörg-M. Neudörfl; Harald Gröger
• Keywords: 01 natural sciences; 0104 chemical sciences

A practical one-pot procedure for the preparation of Singh's catalyst from either l-/d-proline or Boc-proline is described. The coupling partner, a chiral amino alcohol, can be prepared and used directly without purification corresponding acid ester. Moreover, tert-butoxycarbonyl (Boc) group removal using concentrated HCl in MeOH–DCM was developed utilized multigram-scale synthesis catalyst.