Compounds of formula (I), wherein R1 and R2 are, independently of one another, H, C1-C6alkyl, C1-C6halogenalkyl, C1-C6alkoxy, C1-C6alkoxy-C1-C6alkyl, or C1-C6alkoxy-C1-C6alkyloxy, and R3 is C1-C6alkyl, are obtainable in high yields by stereoselective addition of R3-substituted propionic acid esters to R1- and R2-substituted benzaldehydes of formula R-CHO to form corresponding 3-R-3-hydroxy-2-R3-propionic acid esters, conversion of the OH group to a leavaing group, subsequent regioselective elimination to form 3-R-2-R3-propenic acid esters, and their hydrolysis to form corresponding propenic carboxylic acids and their enantioselective hydrogenation, wherein R is (a).
                            公式(I)的化合物,其中R1和R2分别是H、C1-C6烷基、C1-C6卤代烷基、C1-C6烷氧基、C1-C6烷氧基-C1-C6烷基或C1-C6烷氧基-C1-C6烷氧基,而R3是C1-C6烷基,可以通过将R3取代的
丙酸酯立体选择性地加成到公式R-CHO的R1和R2取代
苯甲醛中,形成相应的3-R-3-羟基-2-R3-
丙酸酯,将OH基团转化为离去基团,随后选择性地消除以形成3-R-2-R3-
丙烯酸酯,再通过
水解形成相应的
丙烯酸羧酸及其对映选择性氢化,其中R是(a),可以高产得到。