A proof-of-principle methodology is presented in which all commercially-available cysteine (Cys) and selenocysteine
(Sec) solid phase peptide synthesis (SPPS) derivatives are synthesized in high yield from easily prepared protected
dichalcogenide precursors. A Zn-mediated biphasic reduction process applied to a series of four bis-Nα-protected
dichalcogenide compounds allows facile conversion to their corresponding thiol and selenol intermediates followed by insitu
S- or Se-alkylation with various electrophiles to directly access twenty one known Cys and Sec SPPS derivatives.
Most of these derivatives were able to be precipitated in crude form out of petroleum ether in sufficient purity for direct
use as peptide building blocks. Subsequent incorporation of these derivatives into peptide models nicely illustrates their
viability and applicability toward SPPS.
Keywords: Cysteine protection, selenocysteine protection, peptide synthesis.
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