Synthesis and use of benzyl tert-butyl iminodicarbonate, a versatile reagent for the preparation of amines

Abstract

An efficient synthesis of benzyl tert-butyl iminodicarbonate (IV), starting from benzoyl isocyanate, is reported. Reaction of the isocyanate with benzyl alcohol gave benzyl N-benzoylcarbamate (II) which on exhaustive tert-butoxycarbonylation via the non-isolated triacyl amine III, after aminolysis, provided the title compound. The sodium salt V was alkylated with various halides under Gabriel conditions to give in high yields the corresponding benzyloxycarbonyl tert-butoxycarbonyl diprotected amines. Similarly, compound IV was alkylated with alcohols under Mitsunobu conditions to give some additional amines of this type, from which the protecting groups can be removed selectively under mild conditions.