Reaction of aldehydes with stabilized sulfur ylides. Highly stereoselective synthesis of 2,3-epoxy-amides
作者:María Valpuesta Fernández、Patricia Durante-Lanes、Fidel J. López-Herrera
DOI:10.1016/s0040-4020(01)90089-4
日期:1990.1
2-nitro-benzaldehyde (1d), gives a 15:1 mixture (trans-cis) of analogous products 3d. Reaction of 2 with 2,3-O-isopropylidene-D-glyceraldehyde (4) results in a highly stereoselective synthesis of (2S,3R,4R)- and (2R,3S,4R)-N,N-dimethyl-2, 3-epoxy-4,5-o-isopropylidene-4,5-dihydroxypentanoamides (5a) and (5b), (86:14 at r.t., 96:4 at -5 to 0°C, 5a:5b). Configurational analysis was made by three different
苯甲醛(1a),4-氯苯甲醛(1b)或3-硝基苯甲醛(1c)与N,N-二甲基-2-(二甲基磺酰亚氨基)乙酰胺(2)的反应仅产生反式-3-苯基-2,3-缩水甘油酰胺衍生物3a-c的收率很高。与2-硝基苯甲醛(1d)的相同反应,得到类似产物3d的15:1混合物(反式-顺式)。的反应2与2,3- ö异亚丙基d甘油醛(4中的(2S,3R,4R)的高度立体选择性合成)的结果-和(2R,3S,4R)-N,N-二甲基-2, 3-环氧-4,5-邻-异亚丙基-4,5-二羟基戊酰胺(5a)和(5b),(室温下86:14,-5至0℃下96:4,5a :5b)。通过三种不同的方法进行构型分析:1)1 H-NMR偶合常数分析;2)与通过顺式或反式烯烃13和12的环氧化制备的顺式-反式类似物15a,b和7a,b的比较;和3)5a,7a和15a(或5b,7b和15b)的转换)异构体变成已知的(3S,4R)-3,4,5-三羟基戊酸1