Lewis acid catalysed preparation of some carbamates and sulphonylureas. Application to the determination of enantiomeric purity of chiral alcohols

Abstract

Lewis acids such as boron trifluoride–diethyl ether and aluminium chloride catalyze the reaction of alcohols and sulphonamides with isocyanates, affording carbamates and sulphonylureas, respectively, in acceptable yield. Applied to the formation of diastereoisomeric carbamates from chiral alcohols using Pirkle's reagents, [(R)- and (S)-1-(1 -naphthyl)ethyl isocyanate (NPEI)], this technique provides a convenient method for determination of enantiomeric purity.