Chiral synthesis of asymmetrically tetra-C-substituted cyclopentane derivatives by Diels-Alder addition of cyclopentadiene to unsaturated acyclic-sugar derivatives
作者:Derek Horton、Tomoya Machinami、Yasushi Takagi
DOI:10.1016/0008-6215(83)84013-0
日期:1983.9
cyclopentadiene in boiling toluene to give 40% of a crystalline, norbornene adduct (3) having the 5S-exo ester, 6S-endo sugar-chain configuration, as established by crystallography and by conversions into the known, crystalline (2S,3S)-bis(p-tolylsulfonyloxymethyl)bicyclo[2.2.1]heptane. Likewise, the L enantiomer (19) of 2 was converted into the crystalline enantiomer of 3; chromatographic resolution of the
通过将环戊二烯立体控制地加成到反式α,β-不饱和糖衍生物中,已经获得了在合成前列腺素类似物中所需要的光学纯的取代的环戊烷衍生物。(E)-4,5,6,7-四-O-乙酰基-2,3-二脱氧-D-阿拉伯糖-庚-2-烯酸酯(2),是通过在Wittig中将Ph3PCHCO2Me加到醛-D-阿拉伯糖中获得四乙酸酯,与环戊二烯在沸腾的甲苯中反应,得到40%的结晶降冰片烯加合物(3),具有结晶5S-外酯,6S-内糖链构型,并通过转化为已知的结晶(2S) ,3S)-双(对甲苯磺酰氧基甲基)双环[2.2.1]庚烷。同样,将2的L对映体(19)转化为3的结晶对映体;反应中其他狄尔斯-阿尔德加合物的色谱分离得到较少量的其他三种可能的异构体加合物,其特征在于适当的转化。2,3:4,5-二-O-异亚丙基-醛-D-阿拉伯糖与环戊二烯在热甲苯中的Ph3PCHCO2Me Wittig加合物(9)可分离得到5S,6S异构体加合