Effect of Phase-Transfer Catalyst on Stereochemistry of<i>tert</i>-Butyl-3-aryl(alkyl)-Substituted Glycidates
作者:Anna Kowalkowska、Andrzej Jończyk
DOI:10.1021/op1000379
日期:2010.5.21
Darzen’s condensation of tert-butyl-chloroacetate with aromatic, α,β-unsaturated, and aliphatic aldehydes in the presence of sodium hydroxide, afforded tert-butyl-glycidates, with trans/cis ratios 2.38−7.75. When TBAB was added as catalyst, the ratio reversed to cis/trans 1.67−4.52. Rate constants of halohydrin anion formations, their cyclization, and hydrolysis of diastereoisomers of glycidates as
在氢氧化钠的存在下,叔丁基氯乙酸酯与芳族,α,β-不饱和脂族醛和脂肪族醛的Darzen缩合反应,得到缩水甘油酸叔丁酯,反式/顺式比为2.38-7.75。当添加TBAB作为催化剂时,该比例反转为顺式/反式1.67-4.52。卤代醇阴离子形成的速率常数,它们的环化,缩水甘油酯的非对映异构体的水解以及卤代醇阴离子的相应构象异构体的结构被认为可以解释这些结果。