Nonsolvent Application of Ionic Liquids: Organo-Catalysis by 1-Alkyl-3-methylimidazolium Cation Based Room-Temperature Ionic Liquids for Chemoselective N-tert-Butyloxycarbonylation of Amines and the Influence of the C-2 Hydrogen on Catalytic Efficiency
Anirban Sarkar, Sudipta Raha Roy, Naisargee Parikh and Asit K. Chakraborti*
*Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar 160 062, Punjab, India, Email: akchakrabortiniper.ac.in
A. Sarkar, S. R. Roy, N. Parikh, A. K. Chakraborti, J. Org. Chem., 2011, 76, 7132-7140.
DOI: 10.1021/jo201102q (free Supporting Information)
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1-Alkyl-3-methylimidazolium cation based ionic liquids efficiently catalyze N-tert-butyloxycarbonylation of amines with excellent chemoselectivity. The catalytic role of the ionic liquid is envisaged as electrophilic activation of di-tert-butyl dicarbonate (Boc2O) through bifurcated hydrogen bond formation with the C-2 hydrogen of the 1-alkyl-3-methylimidazolium cation.
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