267901-32-6Relevant academic research and scientific papers
Asymmetric Synthesis of 4-Aryl-3,4-dihydrocoumarins by N-Heterocyclic Carbene Catalyzed Annulation of Phenols with Enals
Li, Guo-Tai,Li, Zhi-Ke,Gu, Qing,You, Shu-Li
, p. 1318 - 1321 (2017)
The highly enantioselective synthesis of 4-aryl-3,4-dihydrocoumarins was realized through direct annulation of phenols with enals catalyzed by dihydroisoquinoline-type NHC (DHIQ-NHC), an N-heterocyclic carbene derived from l-phenylalanine. The catalytic reaction proceeds with a wide scope of electron-rich phenols and enals providing structurally diverse 4-aryl-3,4-dihydrocoumarins in good to excellent yields and enantioselectivity. This method was useful in the synthesis of natural products and biologically relevant compounds from readily available starting materials.
α,β-Unsaturated acyl azoliums from N-heterocyclic carbene catalyzed reactions: Observation and mechanistic investigation
Mahatthananchai, Jessada,Zheng, Pinguan,Bode, Jeffrey W.
supporting information; experimental part, p. 1673 - 1677 (2011/04/21)
Caught in the act: Acyl azoliums have long been thought to be key reactive intermediates in N-heterocyclic carbene catalysis, but they have never been observed under catalytic conditions. Now, this has been successfully achieved by the characterization of α,β-unsaturated acyl azoliums (see scheme) using different spectroscopic techniques. Kinetic studies revealed the origin of their unexpected chemoselectivity in acylation and annulation reactions.
