Enantioselective Synthesis of 2-Substituted 2-Phenylethylamines by Lithiation−Substitution Sequences: Synthetic Development and Mechanistic Pathway
作者:Jason M. Laumer、Dwight D. Kim、Peter Beak
DOI:10.1021/jo0258251
日期:2002.9.1
The lithiation and asymmetric substitution of N-(2-phenylethyl)isobutyramide (2) with selected electrophiles, under the influence of (-)-sparteine, provides benzylically substituted products in 58-90% yields with enantiomeric ratios (ers) from 72:28 to 91:9. Syntheses of enantioenriched dihydroisoquinolines (S)-18 and (S)-19 and a tetrahydroisoquinoline (4S)-20 provide examples of synthetic applications
N-(2-苯乙基)异丁酰胺(2)的锂化和不对称取代(在选定的亲电试剂的作用下)在(-)-天冬氨酸的作用下以58-90%的产率提供苄基取代的产物,对映体比率(ers)为72: 28至91:9。富含对映体的二氢异喹啉(S)-18和(S)-19和四氢异喹啉(4S)-20的合成提供了合成应用的实例。机理研究表明,在-78摄氏度下对映体确定步骤是动态热力学分辨率。