Asymmetric synthesis of (2R,3S)-4-halo-3-benzyloxy-2-(N-methoxycarbonyl-N-benzylamino)butyronitriles as precursors for the synthesis of β-hydroxy-α-amino acids
作者:Ramón Badorrey、Carlos Cativiela、Marı́a D Dı́az-de-Villegas、José A Gálvez
DOI:10.1016/s0957-4166(00)00022-7
日期:2000.3
3S)-2-benzylamino-3-benzyloxy-4-(tert-butyldimethylsilyloxy)butyronitrile, which is readily available in diastereomerically pure form by a Strecker-type reaction of the N-benzylimine, derived from selectively protected (R)-glyceraldehyde, and trimethylsilyl cyanide. These compounds enable the facile synthesis of chiral β-hydroxy-α-amino acids containing virtually any nucleophile capable of substituting
(2 R,3 S)-4-卤代-3-苄氧基-2-(N-甲氧基羰基-N-苄基氨基)丁腈已通过有效的三步法从(2 R,3 S)-2-苄基氨基制备-3-苄氧基-4-(叔-butyldimethylsilyloxy)丁腈的方法,是在由一个斯特雷克尔型反应非对映异构纯的形式容易得到ñ -benzylimine,从选择性地衍生保护(ř)-甘油醛和三甲基甲硅烷基氰化物。这些化合物使得能够容易地合成实际上包含能够取代γ-卤素原子的任何亲核试剂的手性β-羟基-α-氨基酸。作为其合成潜力的例证,该4-溴衍生物已成功转化为(1 R,2 R)-2-苄氧基-1-(N-甲氧基羰基-N-苄氨基)环丙烷甲酰胺,这是一种新的构象受限的丝氨酸类似物,分两个步骤:碱诱导的环化和随后的腈基水解。