Absolute Configuration Assignment by Asymmetric Syntheses of the Homalium Alkaloids (−)-(<i>R</i>,<i>R</i>,<i>R</i>)-Hoprominol and (−)-(4′<i>S</i>,4″<i>R</i>,2‴<i>R</i>)-Hopromalinol
作者:Stephen G. Davies、James A. Lee、Paul M. Roberts、Jeffrey P. Stonehouse、James E. Thomson
DOI:10.1021/jo301830j
日期:2012.11.2
assigned for the first time as (−)-(R,R,R)-hoprominol and (−)-(4′S,4″R,2‴R)-hopromalinol. The asymmetric syntheses of (−)-(R,R,R)-hoprominol (in 10 steps and 4.0% overall yield) and (−)-(4′S,4″R,2‴R)-hopromalinol (in 10 steps and 9.3% overall yield), from commercially available starting materials in each case, therefore represent the first total asymmetric syntheses of these alkaloids to be reported
锂(R)-N-(3-氯丙基)-N-(α-甲基苄基)酰胺共轭加成到α,β-不饱和酯中的步骤是合成ho碱生物碱Hoprominol的所有可能的非对映异构体的关键步骤和蛇麻草醇。将这些合成样品的比旋光数据与从天然来源分离的样品的比旋光数据进行比较,可以使这些生物碱中的绝对构型首次确定为(-)-(R,R,R)-异丙肾上腺素和( -)-(4 'S,4″ R,2 ‴ R)-异丙苯丙醇。(-)-(R,R的不对称合成,R)-异丙醇(10步,总收率4.0%)和(-)-(4 'S,4″ R,2 ‴ R)-异丙苯甲醇(10步,总收率9.3%),从商业途径开始因此,在每种情况下这些材料代表了有待报道的这些生物碱的第一个全不对称合成。