Reduction of Ethanethiol Esters to Aldehydes

Abstract

Reduction of ethanethiol esters of α-amino acids to α-amino aldehydes by triethylsilane and catalytic palladium-on-carbon is describ­ed. α-Amino aldehydes with Boc, Cbz, or Fmoc protection could be obtained without racemization in high yield.

Key words

reductions - aldehydes - thiol esters - amino aldehydes

References

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• 2 For a review on α-amino aldehydes, see: Jurczak J. Golebiowski A. Chem. Rev.  1989,  89:  149 
• In Procedure 2, the optical purity of the resulting α-amino aldehyde was determined by the following procedure. An amide was obtained via a three-step sequence:
• 3a

  NaBH₄, EtOH;

• 3b

  10% Pd/C, H₂, EtOH;

• 3c

  (R)-(+)-MTPA, DCC, MeCN]. No peak due to N-Cbz-d-phenylalaninal (δ = 3.29) was detected (Scheme [2] ).

  

  Scheme 2

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