1,1'-Carbonylbis(3-methylimidazolium) Triflate: An Efficient Reagent for Aminoacylations

Article abstract of DOI:10.1021/ja00195a043

Amino acid carboxyl activation and subsequent coupling with nucleophiles frequently suffer from uncertain risks of racemization, complex reagent preparation, or troublesome side-product removal.All of these difficulties are eliminated with a new, simple reagent, 1,1'-carbonylbis(3-methylimidazolium) triflate (CBMIT), obtainable readily by bis-alkylation of carbonyldiimidazole with methyl triflate.Via a highly reactive acyl imidazolium intermediate, CBMIT couples amino acid components or amino acids and alcohols to give peptides and esters, easily isolated in high yield.The reaction medium remains free of any base, and no loss of optical activity is observed.