Diastereo- and enantioselective additions of α-nitro esters to imines for <i>anti</i>-α,β-diamino acid synthesis with α-alkyl-substitution
作者:Daniel J. Sprague、Anand Singh、Jeffrey N. Johnston
DOI:10.1039/c7sc05176j
日期:——
The discovery that a C2-symmetric bis(AMidine) [BAM] catalyst promotes an anti-selectiveaddition of α-substituted α-nitro esters to imines is described, providing α-substituted α,β-diamino ester products with high diastereo- and enantioselectivity. When compared to the function of a BAM catalyst reported previously, the pair offer a rare example of diastereodivergence using a bifunctional Brønsted
A Diastereo- and Enantioselective Synthesis of α-Substituted <i>syn</i>-α,β-Diamino Acids
作者:Anand Singh、Jeffrey N. Johnston
DOI:10.1021/ja8011808
日期:2008.5.1
Highly diastereo- and enantioselective additions of substituted alpha-nitroesters to imines have been developed. High diastereoselection relies on the finding that the combination of chiral proton catalyst 2b and alpha-nitro aryl esters bearing 2,6-disubstitution combine to raise substrate-controlled diastereoselection to >20:1 in favor of the syn diastereomer. Furthermore, the chiral catalyst provides