anti-Michael addition of (R)-(+)-1-phenylethylamine to methyl bis(trifluoromethyl)acrylate (1b) leads to a 52:48 mixture of the diastereomeric adducts (S,R)- and (R,R)-3a. After addition of hydrochloric acid, the diastereomeric salt (S,R)-3b crystallizes in a pure form to give, upon hydrogenolysis, an enantiomerically pure hydrochloric adduct of (+)-methyl hexafluorovalinate [(S)-4] to which the (S)-configuration was assigned. Treatment of (R,R)-3a with BBr3 gave hexafluorovaline [(R)-5].
将(R)-(+)-1-苯基
乙胺与双(三
氟甲基)
丙烯酸甲酯(1b)进行反迈克尔加成,生成非对映异构体加成物(S,R)-和(R,R)-3a 的 52:48 混合物。加入
盐酸后,非对映异构盐 (S,R)-3b 结晶为纯净物,氢解后得到对映体纯净的(+)-六
氟戊酸甲酯盐酸盐加合物[(S)-4],其(S)-构型被分配给该加合物。用 BBr3 处理 (R,R)-3a,得到
六氟丙烯[(R)-5]。