Planar Chiral PHANOLs as Double Hydrogen Bonding Donor Organocatalysts: Synthesis and Catalysis
作者:D. Christopher Braddock、Iain D. MacGilp、Benjamin G. Perry
DOI:10.1002/adsc.200404065
日期:2004.8
4,12-Dihydroxy[2.2]paracyclophanediol (PHANOL; 1), and its para-substituted derivatives 2, 5 and 7, were found to catalyse Diels–Alder cycloadditions of α,β-unsaturated aldehydes or ketones with dienes and/or epoxide ring opening reactions with amines. The mode of catalysis by the PHANOLs is via double hydrogen bonding to the two sp2 lone pairs of a carbonyl group or the two lone pairs of the epoxide
发现4,12-二羟基[2.2]对环庚二醇(PHANOL; 1)及其对位取代的衍生物2、5和7可以催化α,β-不饱和醛或酮与二烯和/或环氧化物的狄尔斯-阿尔德环加成反应与胺的开环反应。PHANOLs的催化方式是通过氢键与羰基的两个sp 2孤对或环氧化物的两个孤对进行双氢键合。该PHANOLs的Diels-Alder反应的催化活性的顺序基本上与基于的吸电子基团的能力(一个或多个)的程度在预期的氢键供体强度相关的对位置。相反,由于对双氢键模式的空间干扰,邻位取代的PHANOL 10、11和14没有活性作为催化剂。为支持所提出的双氢键模式,讨论了各种PHANOL的1 H NMR和IR光谱数据。