作者:Geoffrey D. Coxon、Juma R. Al-Dulayymi、Mark S. Baird、Stefan Knobl、Evan Roberts、David E. Minnikin
DOI:10.1016/s0957-4166(03)00165-4
日期:2003.5
(11R,12S)-Lactobacillic acid has been prepared from 2,3-O-isopropylidene-D-glyceraldehyde, in a sequence involving asymmetric cyclopropanation, and from cis-cyclopropane-1,2-dimethanol, using enzymatic desymmetrisation. The key step in the former route was the stereochemically controlled cyclopropanation of (1Z,4'S)-(2',2'-dimethyl-1',3'-dioxolan-4'-yl)-1-octene via a Simmons-Smith type reaction, using diethylzinc and chloroiodomethane. This product was converted into the key intermediate (1R,2S)-1-formyl-2-hexylcyclopropane, which was also obtained by a known sequence from the (1R,2S)-monobutyrate ester of cis-cyclopropane-1,2-dimethanol. This pivotal aldehyde was converted into (11R,12S)-lactobacillic acid. Using analogous chemistry, the (11S,12R)-enantiomer of lactobacillic acid was prepared from 2,3-O-isopropylidene-D-glyceraldehyde or from the (1S,R)-monobutyrate ester of cis-cyclopropane-1,2-dimethanol. (C) 2003 Elsevier Science Ltd. All rights reserved.
(LS,12S)-
乳酸杆菌酸已从2,3-O异
丙烯基-D-
甘油醛中制备,其中涉及非对映异构物
环丙烷化,以及从顺式
环丙烷-1,2-二
甲醇中使用酶催化去对称化。前一条路线的关键步骤是通过对(1Z,4S')-(2',2'-二甲基-1',3'-二氧杂
环戊烷-4'-基)-1-
辛烯进行Simmons-Smith型反应进行立体
化学控制的
环丙烷化,使用了
二乙基锌和
碘氯甲烷。该产品被转化为关键中间体(1R,2S)-1-甲酰基-2-
己基环丙烷,该中间体也可通过已知路线从顺式
环丙烷-1,2-二
甲醇的(1R,2S)-单
丁酸酯获得。这种关键的醛被转化为(11R,12S)-
乳酸杆菌酸。通过类似
化学,
乳酸杆菌酸的(11S,12R)-对映异构体从2,3-O异
丙烯基-D-
甘油醛或顺式
环丙烷-1,2-二
甲醇的(1S,R)-单
丁酸酯中制备。 (C) 2003 Elsevier Science Ltd. 保留所有权利。