1. Lewis acid facilitated regioselective synthesis of τ-histidinoalanine.
- Author
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Wu, Ju, Ma, Bing, Wang, Yuehui, Zhang, Yue, Yan, Shenghu, and Castle, Steven L.
- Subjects
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LEWIS acids , *REGIOSELECTIVITY (Chemistry) , *CHEMICAL synthesis , *ALANINE , *CROSSLINKING (Polymerization) , *BIOACTIVE compounds - Abstract
Abstract: τ-Histidinoalanine, with an unusual cross-link between His and Ala, is the central component of theonellamides, a family of bioactive peptidic natural products. Previous syntheses of this residue were plagued with low regioselectivity in the alkylation step. Herein, we report two novel routes to τ-histidinoalanine, involving alkylation of Boc-His-OMe with a serine-derived β-lactone and β-bromoalanine, respectively, as the electrophiles. The use of Mg(OTf)2 as a catalyst was found to be essential to ensure high regioselectivity for the τ-isomer, presumably due to the formation of a six-membered ring chelation involving the π-nitrogen atom of histidine. [Copyright &y& Elsevier]
- Published
- 2014
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