A Formal [3,3]-Sigmatropic Rearrangement Route to Quaternary α-Vinyl Amino Acids: Use of Allylic N-PMP Trifluoroacetimidates

Authors

David B. Berkowitz, University of Nebraska - LincolnFollow
Bin Wu, University of Nebraska - Lincoln
Huijie Li, University of Nebraska - Lincoln

Date of this Version

3-2-2006

Citation

Org Lett. 2006 March 2; 8(5): 971–974.

Comments

Copyright 2006. Used by permission.

Abstract

Pd(II)-mediated rearrangement of allylic N-PMP (p-methoxyphenyl) trifluoroacetimidates provides the first formal sigmatropic route to quaternary, α-vinylic amino acids, potential suicide substrates for PLP-enzymes. The amino acid side chains enter via transition metal-mediated C-C bond constructions, including (i) Cu(I)-mediated conjugate addition (Ala); (ii) Pd(0)/AsPh₃-mediated Stille coupling (Allyl-Gly, Phe, DOPA, m-Tyr) and (iii) Pd(0)/Pt-Bu₃-mediated Negishi coupling (Leu). In the synthesis of the DOPA decarboxylase inactivator, α-vinyl-m-tyrosine, the new N-PMP trifluoroacetimidate rearranges much more efficiently than the corresponding trichloroacetimidate.