Conformational change in a urea catalyst induced by sodium cation and its effect on enantioselectivity of a Friedel-Crafts reaction
作者:Arjun K. Chittoory、Gayatri Kumari、Sudip Mohapatra、Partha P. Kundu、Tapas K. Maji、Chandrabhas Narayana、Sridhar Rajaram
DOI:10.1016/j.tet.2014.03.068
日期:2014.5
indeed in an unfavorable conformation. Infrared and Raman spectroscopic studies show that sodium binds the catalyst through the carbonyl and sulfonyl groups. Simulated IR and Raman spectra match well with the experimentally recorded spectra, thereby corroborating the proposed conformational change. This result shows that weak Lewis acids can be used to tune the conformation of hydrogen-bonding catalysts
Catalytic Enantioselective Additions of Indoles to Nitroalkenes
作者:Madhu Ganesh、Daniel Seidel
DOI:10.1021/ja8063292
日期:2008.12.10
A new design principle that provides access to more active thiourea catalysts is described. Highly enantioselective additions of indoles to nitroalkenes are reported using a new quinolinium thioamide catalyst.