Selective 4,6-O-benzylidene formation of methyl α-d-mannopyranoside using 2,6-dimethylbenzaldehyde
作者:Louis J. Liotta、Jennifer F. Chalmers、Jessica N. Falco Marshall、Timothy E. Ferreira、Hannah E. Mullen、Nicholas J. Pace
DOI:10.1016/j.carres.2014.02.024
日期:2014.6
While methyl alpha-d-glucopyranosides and alpha-d-galactopyranosides selectively form 4,6-O-benzylidenes when reacted with excess benzaldehyde in the presence of acid catalyst methyl alpha-d-mannopyranosides does not exhibit the same selectivity because of the cis-arrangement of the C2 and C3 hydroxyl groups. The selectivity for the 4,6-O-benzylidene is restored by using 2,6-dimethylbenzaldehyde instead
当甲基α-d-吡喃葡萄糖苷和α-d-吡喃半乳糖苷在酸催化剂存在下与过量的苯甲醛反应时选择性地形成4,6-O-亚苄基,由于顺式- C2和C3羟基的排列。通过使用2,6-二甲基苯甲醛而不是苯甲醛来恢复对4,6-O-亚苄基的选择性。另外,过量的2,6-二甲基苯甲醛很容易通过用石油醚萃取而从反应中回收,并且可以在不进一步纯化的情况下重复使用。就化学合成而言,2,6-二甲基亚苄基表现出与未取代的亚苄基相似的性质。