A Simple and Powerful tert-Butylation of Carboxylic Acids and Alcohols

A simple and safe tert-butylation reaction was developed. Treatment of various free amino acids with 1.1 equiv of bis(trifluoromethanesulfonyl)imide in tert-butyl acetate directly afforded tert-butyl esters with free amino groups quickly and in good yields. In addition, various carboxylic acids and alcohols without amino groups were converted to tert-butyl esters and ethers in high yields with small catalytic amounts of bis(trifluoromethanesulfonyl)imide. All tert-butylation reactions of free amino acids, carboxylic acids, and alcohols proceeded much faster and in high yields compared to conventional methods.