Enantioselective Organocatalytic Addition of Azlactones to Maleimides: A Highly Stereocontrolled Entry to 2,2-Disubstituted-2H-oxazol-5-ones
作者:Andrea-Nekane R. Alba、Guillem Valero、Teresa Calbet、Mercé Font-Bardía、Albert Moyano、Ramon Rios
DOI:10.1002/chem.201000239
日期:2010.8.23
The first highly diastereo‐ and enantioselectiveorganocatalytic synthesis of 2,2‐disubstituted‐2H‐oxazol‐5‐ones is described. The addition of oxazolones to maleimides is promoted by bifunctional thiourea catalysts, which afford the corresponding 2,2‐disubstituted‐2H‐oxazol‐5‐ones with total regio‐ and stereocontrol.
Asymmetric organocatalytic Michael addition of azlactones to cis-1,2-bis(phenylsulfonyl)ethene. A simple entry to quaternary α-amino acids
作者:Natalia Bravo、Andrea-Nekane R. Alba、Guillem Valero、Xavier Companyó、Albert Moyano、Ramon Rios
DOI:10.1039/c0nj00321b
日期:——
Azlactones react with 1,2-bis(phenylsulfonyl)ethene under catalysis by simple chiral thioureas, affording α,α-disubstituted α-amino acid derivatives in good yields and in moderate to good enantioselectivities.