Boc

Boc, in chemistry, most commonly refers to the tert-butyloxycarbonyl protecting group. The Boc group is used to temporarily mask amine functionalities during organic synthesis and peptide chemistry, enabling selective reactions at other sites. It is introduced to amines with di-tert-butyl dicarbonate (Boc2O) in the presence of a base, forming a Boc-protected amine. The group is valued for its stability under many reaction conditions, including numerous bases and various reagents, which helps in multi-step sequences.

Deprotection of Boc-protected amines is typically achieved under acidic conditions, most commonly with trifluoroacetic acid (TFA) or hydrogen chloride in an organic solvent. The Boc group is acid-labile and its removal regenerates the free amine, releasing carbon dioxide and tert-butyl-containing byproducts. This deprotection step is a standard feature of traditional Boc-based routes in peptide synthesis and other sequences where amine protection is required.

In the broader context of protecting groups, Boc is one option among several amine-protecting strategies. Alternatives include Fmoc, which is base-labile, and Cbz, which uses hydrogenolysis for removal. The choice of protecting group depends on the specific substrate, sequence length, and downstream chemistry.

Other uses of the acronym Boc exist outside chemistry, though they are unrelated to the protecting group. For example, BoC (often written with capitalization) can refer to the Bank of Canada, or, in industrial history, BOC/Gases, a former British oxygen and gases company now part of larger corporations. The chemical Boc remains the most widely used meaning of the term in scientific literature.