The difficult functionalization of fragments in the presence of covalent warheads limits synthetic flexibility and late-stage diversification and slows design-make-test cycles. We considered that the N-silyl BCB-sulfoximine may facilitate further diversification. Pleasingly, the TBDPS group could be readily removed from 2a with TBAF to form BCB-NH-sulfoximine 5a in high yield and maintaining the BCB integrity (Scheme 3). The same NH sulfoximine 5a was also prepared by NH transfer to BCB-sulfoxide 2h using diacetoxyiodobenzene and ammonium carbamate. The NH sulfoximine was characterized by X-ray crystallography indicating a sterically minimized conformation with the BCB ring sitting between sulfoximine nitrogen and oxygen atoms. The bridgehead C-C bond length is 1.498(3) Å, similar to reported bond lengths in other BCB derivatives. Deprotonating the sulfoximine-NH with NaH followed by trapping with various electrophiles enabled a variety of N-functionalization with Boc, Piv, acetyl and mesyl groups (6a-6d), as well as alkylation with methyl and propargyl groups (6e-6f), the latter installing a click handle. Moreover, BCB-NH-sulfoximine 5a underwent palladiumcatalyzed N-arylation to afford N-aryl and N-heteroaryl BCB sulfoximines in good yields (6g-6h), presenting a viable route to install more complex aryl halides and significantly broadening the types of BCB sulfoximines that could be accessed. We envisaged that the sulfoximine motif may stabilize lithiated derivatives for bridgehead functionalization by coordination and steric protection. Indeed, treating TBDPSprotected BCB sulfoximine with n-BuLi led to successful bridgehead lithiation and functionalization with a range of electrophiles. Methyl (7a, MeI) and benzyl (7b, BnBr) BCB sulfoximines were isolated in good yields after in situ TBDPS deprotection. The lithiated BCB also reacted with I2, TMSCl, benzaldehyde and ethyl chloroformate to afford the corresponding products 7c-7f. Trapping the lithiated intermediate with carbon dioxide generated carboxylic acid 7g directly in excellent yield, providing a handle for potential further diversification and reactivity modification. Using enantioenriched p-bromophenyl BCB sulfoximine (S)-2b tolyl and pyridyl substituents were successfully installed by palladium-catalyzed Suzuki-Miyaura cross-coupling, affording (S)-8a and (S)-8b in moderate yields and retention of ee. Buchwald amination conditions were applied using N-Boc piperazine to generate the aniline product (S)-8c. Sonogashira coupling followed by deprotection gave alkyne (S)-8d. The excellent tolerance of the BCB motif itself under basic conditions at elevated temperatures is notable.