Carbenes-catalyzed activation of aldehyde for phenol functionalization

Abstract

Phthalides are a crucial kind of compounds in both of natural products and pharmaceutical molecules, which exhibit a broad spectrum of biological activities. In particular, 3-Ylidenephthalides represent satisfactory activity on anti-HIV, anti- inflammatory and anti-cancer. Consequently, a numerous of literatures have reported the methods to synthesis this series of compounds. However so far, most of these methods need to rely on transition metal catalysts. Besides, the expenses of the metal catalyst and the metal contamination of the product remain to be a pending issue. Herein we report the first example of NHC-catalyzed activation of aldehyde for phenol functionalization, which could consider to be an eco-friendly and highly efficient method for chiral synthesis of phthalide derivatives. My topic will be divided into two parts: Chapter I gives a brief introduction on N-Heterocyclic Carbene in organocatalysis. From it was first separated to it was applied to catalyze various kinds of reaction (Benzoin condensation, Stetter reaction and etc). Followed by its series of extended Breslow intermediates such as homoenolate, acylazolium and azolium enolate. Chapter II introduces our initial attempt on a one-step and enantioselective approach to activate aldehyde for phenol functionalization through using N-Heterocyclic Carbene as the catalyst.