*WINNER* Cleavage of tert-Butoxycarbonyl (BOC) Groups from Indoles and Other Heterocycles Using an Addition-Elimination Strategy with 3-Methoxypropylamine.

Abstract

In the pursuit of synthesizing unsymmetrical complexant molecules with frustrated Lewis pairs for potential use in SANEX-type processes, a recently published method has been developed for the cleavage of BOC-protecting groups on various deactivated substrates. Under mild conditions, BOC-protected indoles, 1,2-indazoles, imidazoles, and 1,2-pyrazoles were deprotected utilizing addition-elimination reactions with nucleophilic primary amines. In comparison to more common BOC-deprotection methods, such as treatment with mineral acids, reducing agents, or Lewis acids, these mild conditions afford a feasible means to deprotect heterocycles that are acid sensitive, thereby expanding the scope of potential protection-deprotection synthetic methodologies relevant to many branches of chemistry. Synthesis of BOC-protected substrates, condition optimization, purification protocol, and substrate scope will be discussed.