Dimethyl(methylthio)sulfonium tetrafluoroborate: A reagent for disulfide bond formation in peptides

Structural analysis of fertilinβ cyclic peptide mimics that are ligands for α6β1 integrin

“…After purification of the cyclized peptide, the Acm group of the N‐terminus Cys was removed with dimethyl(methylthio)sulfonium tetrafluoroborate to form the methyl thiol disulfide (26). The reaction mixture was chromatographed (5–65% CH 3 CN over 1 h) to provide the methylthiol protected peptide.…”

Stepwise Construction of Disulfides in Peptides

“…The good stability of S−Acm under acidic cleavage conditions has made the S−Acm‐protected peptide a common synthetic intermediate. It has also promoted the development of a number of alternative conditions for this conversion that involve AgOTf ⋅ DMSO/HCl, NCS, NIS, ICN, silyl chloride‐sulfoxide, dimethyl(methylthio)sulfonium tetrafluoroborate [(CH 3 ) 2 S + −SCH 3 BF 4 − ] . Despite the fact that multiple methods can be used for this conversion, the classic I 2 oxidation remains preferable due to its simplicity and generally good results, particularly for sequences without oxidation‐sensitive residues.…”

One-Pot Peptide Ligation–Desulfurization at Glutamate

“…35 We envisaged that this peptide could be easily accessed via a ligation reaction between two fragments, namely, peptide thioester 16, corresponding to teriparatide (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) and bearing a C-terminal Met residue, and peptide 17 possessing an N-terminal γ-thiol-Glu residue, representing teriparatide (19-38) (Scheme 4). To this end, peptide 18 corresponding to teriparatide (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) was first synthesized on trityl chloride resin using standard Fmoc-SPPS procedures (see SI for synthetic details). Coupling of the γ-thiol-Glu building block 10 and acidic cleavage and deprotection from the resin then afforded the desired peptide fragment 17 in 18% yield after reverse-phase HPLC purification (based on the original resin loading) (Scheme 4).…”