Synthesis of β-Amino Acids: 2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium Tetrafluoroborate (TBTU) for Activation of Fmoc-/Boc-/Z-α-Amino Acids

Abstract

A new and efficient method for the homologation of urethane protected α-amino acids to its β-homomers by the Arndt-Eistert method using TBTU as a coupling agent is described. Several Fmoc-/Boc-/Z-protected α-amino diazoketone derivatives have been obtained as crystalline solids in good yield. The method is found to be rapid and stereospecific.

Keywords:

• L-amino acid
• Homologation
• Diazoketones
• Wolff rearrangement
• Arndt-Eistert approach

Acknowledgments

We thank Professors K. M. Sivanandaiah and B. S. Sheshadri of Bangalore University for useful discussions. We are grateful to Department of Science and Technology, Govt. of India for financial assistance. B. S. P. thanks Bangalore University, Bangalore for financial assistance.