Unusual N-acylation of sterically congested trans-4,5-disubstituted 2-imidazolidinones: remarkably facile CC bond formation

Sterically congested trans-4,5-di-tert-butyl-2-imidazolidinone (DTBIm) and trans-4,5-di-(1-adamantyl)-2-imidazolidinone (DAIm), which are prepared from the parent 1,3-dihydro-2-imidazolone, undergo an unusual N-acylation reaction with acyl chlorides in the presence of organic amines to give the 3-oxoacyl derivatives.