Design of a Bisamidinium Claisen Rearrangement Catalyst for Monodentate Substrates
作者:Venkatachalam R. Annamalai、Elizabeth C. Linton、Marisa C. Kozlowski
DOI:10.1021/ol8026945
日期:2009.2.5
A bisamidinium catalyst has been designed for the Claisen rearrangement. The primary design feature is a dual hydrogen bonding array that can coordinate a singular oxygen atom of the substrate. The ability to function as a dual hydrogen donor is key as the bisamidinium accelerates the Claisen rearrangement to a greater extent than Bronsted acids with lower pK(a) values.
Synthetic utility of 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf)
ene, known as the environmentally benign fluorinated olefin recently employed for the car air-conditioning system, was proved to follow the addition–elimination sequence at its C2 position by the reaction of a variety of alkoxides, forming CF3-containing vinyl ethers in excellent yields.