Application of the Tethered Biginelli Reaction for Enantioselective Synthesis of Batzelladine Alkaloids. Absolute Configuration of the Tricyclic Guanidine Portion of Batzelladine B
作者:Alison S. Franklin、Sylvie K. Ly、Gilbert H. Mackin、Larry E. Overman、A. J. Shaka
DOI:10.1021/jo981971o
日期:1999.3.1
enantiomer of batzelladine B methanolysis product 10 in 10 steps and 25% overall yield from 2-nonanone and methyl acetoacetate. The asymmetric synthesis of 10 establishes that the absolute configuration of the tricyclic portion of batzelladine B (2) is 25aR,28S,30R. The 4-methyl-7-alkyl-1,2,2a,3,4,5,6,7,8,8a-decahydro-5,6,8b-triazaacenaphthalene-3-carboxylic acid subunit, e.g., 29, of batzelladine alkaloids
富含对映体的六氢吡咯并嘧啶8与β-酮酸酯的束缚Biginelli缩合可有效不对称地接近具有角C2a和C8a氢原子同位关系的三环胍9。该反应被用来实现对巴兹拉定生物碱B(2)和E(5)的该片段的第一个实际的对映选择性接近。在10个步骤合成巴兹拉定B甲醇分解产物10的右旋对映异构体中,从2-壬酮和乙酰乙酸甲酯的总产率为25%,可以说明该策略的效率。10的不对称合成表明,batzelladine B(2)的三环部分的绝对构型为25aR,28S,30R。4-甲基-7-烷基-1,2,2a,3,4,5,6,7,8,8a-十氢-5,6,8b-三氮杂ena萘-3-羧酸亚基,例如29,