Studies on the Synthesis of (2R,4?R,8?R)-?-Tocopherol Alternative Syntheses of 2-Chroman-acetic Acid Intermediates
作者:Noal Cohen、John W. Scott、Fred T. Bizzaro、Rocco J. Lopresti、Wayne F. Eichel、Gabriel Saucy、Hans Mayer
DOI:10.1002/hlca.19780610231
日期:1978.3.8
As an extension of previous studies on the total synthesis of (2R,4′R,8′R)-α-tocopherol (1) [1] [2], (S)-(−)-2-(6-benzyloxy-2,5,7,8-tetramethylchroman)acetic acid (6), a pivotal intermediate, possessing the absolute configuration required for construction of 1 was prepared by optical resolution of the racemic modification 11. the latter substance was obtained by two routes, one emanating from the hydroxy
作为对(2R,4'R,8'R)-α-生育酚(1)[1] [2],(S)-(-)-2-(6-苄氧基)的全合成的先前研究的扩展通过消旋外消旋体11的光学拆分,制备了具有形成1的绝对构型的关键化合物-2,5,7,8-四甲基苯并二氢乙酸(6)。后一种物质是通过两种途径获得的,一种途径是从羟基乙缩醛7 [1]发出,另一种途径是基于路易斯酸介导的三甲基氢醌与外消旋-3-羟基-3-甲基戊-4-烯-1-基的环加成反应。醋酸盐(16)得到rac。2-(6-羟基-2,5,7,8-四甲基-苯并二氢吡喃)乙酸乙酯(12)。