A new strategy for the stereoselective synthesis of unnatural α-amino acids

  • Gallos J
  • Sarli V
  • Massen Z
 et al. 
  • 5

    Readers

    Mendeley users who have this article in their library.
  • 41

    Citations

    Citations of this article.

Abstract

A new method for the synthesis of racemic non-proteinogenic α-amino acids has been developed, which involves (i) hetero-Diels-Alder addition of ethyl 2-nitrosoacrylate to electron rich alkenes such as enol ethers, enamines and allylsilanes, (ii) NaCNBH3reduction of the CN bond in the oxazines thus generated, the stereochemistry of the products being controlled by epimerisation of the thermodynamically less stable isomer to the more stable one, (iii) protection of the N-H group as N-Boc and (iv) finally, N-O bond cleavage of both free and protected products to give proline or bis-homoserine derivatives, respectively. An example with concomitant reduction of the carboxylate group, resulting in the formation of the respective amino alcohol is reported. Applying this methodology to a homochiral enol ether, the protected parent d-proline was prepared in enantiomerically pure form, whereas the asymmetric synthesis of the respective bis-homoserine was unsuccessful. Graphical Abstract. © 2004 Elsevier Ltd. All rights reserved.

Author-supplied keywords

  • Allylsilanes
  • Amino alcohols
  • Enamines
  • Enol ethers
  • Ethyl 2-nitrosoacrylate
  • Hetero-Diels-Alder addition
  • α-Amino acids

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • John K. Gallos

  • Zoe S. Massen

  • Anastassia C. Varvogli

  • Constantina Z. Papadoyanni

  • Sofia D. Papaspyrou

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free