Planar Chiral PHANOLs as Organocatalystsfor the Diels-Alder Reaction via Double Hydrogen-Bondingto a Carbonyl Group
作者:D. Christopher Braddock、Iain D. MacGilp、Benjamin G. Perry
DOI:10.1055/s-2003-39890
日期:——
Planar chiral PHANOLs have been shown to catalyze Diels-Alder reactions of α,β-unsaturated aldehydes and ketones with various dienes. Rate accelerations of up to ca. 30-fold were obtained using the electron deficient 4,12-dihydroxy-7,15-dinitro[2.2]paracyclophane as a catalyst. It is proposed that the carbonyl group of the dienophile is activated via a double hydrogen-bonding mode. Although the PHANOLs
平面手性 PHANOL 已被证明可催化 α,β-不饱和醛和酮与各种二烯的 Diels-Alder 反应。速率加速度可达约。使用缺电子的 4,12-二羟基-7,15-二硝基 [2.2] 对环烷作为催化剂获得了 30 倍。建议亲二烯体的羰基通过双氢键模式活化。尽管 PHANOL 本质上是手性的,但在使用对映体纯 (R)-PHANOL 时观察到很少或没有不对称诱导。