Enantioselective Organocatalytic Addition of Oxazolones to 1,1-Bis(phenylsulfonyl)ethylene: A Convenient Asymmetric Synthesis of Quaternary α-Amino Acids
作者:Andrea-Nekane R. Alba、Xavier Companyó、Guillem Valero、Albert Moyano、Ramon Rios
DOI:10.1002/chem.200903025
日期:2010.5.10
A new, easy, and highly enantioselective method for the synthesis of quaternary α‐alkyl‐α‐amino acids based on organocatalysis is reported. The addition of oxazolones to 1,1‐bis(phenylsulfonyl)ethylene is efficiently catalyzed by simple chiral bases or thioureas. The reaction affords α,α‐disubstituted α‐amino acid derivatives with complete C4 regioselectivity and with excellent yields and enantioselectivities
报道了一种基于有机催化合成季α-烷基-α-氨基酸的新型,简便且高度对映选择性的方法。简单的手性碱或硫脲可有效催化将恶唑酮添加到1,1-双(苯磺酰基)乙烯中。该反应提供具有完全C4区域选择性并且具有优异的产率和对映选择性的α,α-二取代的α-氨基酸衍生物。该方法是对先前报道的季铵α-氨基酸的对映选择性方法的补充,可以合成α-苯基-α-烷基-α-氨基酸和α-叔丁基-α-烷基-α-氨基酸。在操作简便,环境友好的条件以及适用于大规模反应方面,它具有明显的优势。