Straightforward Synthesis of (<i>S</i>)- and (<i>R</i>)-α-Trifluoromethyl Proline from Chiral Oxazolidines Derived from Ethyl Trifluoropyruvate
作者:Grégory Chaume、Marie-Céline Van Severen、Sinisa Marinkovic、Thierry Brigaud
DOI:10.1021/ol062593+
日期:2006.12.1
concise synthesis of both enantiomers of alpha-Tfm-proline and (S)-alpha-Tfm-prolinol from ethyl trifluoropyruvate is reported. The key step is a diastereoselective allylation reaction of ethyl trifluoropyruvate and (R)-phenylglycinol-based oxazolidines or imine. The lactone obtained by cyclization of the resulting hydroxy ester proved to be a valuable intermediate for the synthesis of (S)-alpha-Tfm-allylglycine
[结构:见正文]据报道,由三氟丙酮酸乙酯简明地合成了α-Tfm-脯氨酸和(S)-α-Tfm-脯氨醇的对映体。关键步骤是三氟丙酮酸乙酯和基于(R)-苯基甘氨醇的恶唑烷或亚胺的非对映选择性烯丙基化反应。通过环化所得羟基酯获得的内酯被证明是对映体纯形式的(S)-α-Tfm-烯丙基甘氨酸和(S)-α-Tfm-正缬氨酸合成的有价值的中间体。