Selective and Orthogonal Post-Polymerization Modification using Sulfur(VI) Fluoride Exchange (SuFEx) and Copper-Catalyzed Azide–Alkyne Cycloaddition (CuAAC) Reactions

Abstract

Functional polystyrenes and polyacrylamides, containing combinations of fluorosulfate, aromatic silyl ether, and azide side chains, were used as scaffolds to demonstrate the postpolymerization modification capabilities of sulfur(VI) fluoride exchange (SuFEx) and CuAAC chemistries. Fluorescent dyes bearing appropriate functional groups were sequentially attached to the backbone of the copolymers, quantitatively and selectively addressing their reactive partners. This combined SuFEx and CuAAC approach proved to be robust and versatile, allowing for a rare accomplishment: triple orthogonal functionalization of a copolymer under essentially ambient conditions without protecting groups.

Bifluoride-catalysed sulfur(VI) fluoride exchange reaction for the synthesis of polysulfates and polysulfonates

“…For example, propargyl groups in P-12 can serve as handles for the CuAAC-mediated functionalization 5 . Alternatively, the methoxy groups in P-11a were converted into fluorosulfates ( P-11b ) to undergo further SuFEx modification 11 .…”

“…With these catalysts, the reaction between aryl fluorosulfates (or aryl sulfonyl fluorides) and aryl silyl ethers exclusively affords diaryl sulfates (or diaryl sulfonates). The SuFEx reaction has been successfully applied to the synthesis of aromatic polysulfates and polysulfonates by our group 7,8 , and to post-polymerization modifications by others 9–11 .…”

Multidimensional SuFEx Click Chemistry: Sequential Sulfur(VI) Fluoride Exchange Connections of Diverse Modules Launched From An SOF4 Hub

“…Key to SuFEx activation is the requirement for fluoride to transit from a strong covalent bond to a leaving group—a process mediated by 3° amine derived catalysts [8] and thought to involve bifluoride ion and related species. [7, 9–13] …”

Multidimensional SuFEx Click Chemistry: Sequential Sulfur(VI) Fluoride Exchange Connections of Diverse Modules Launched From An SOF4 Hub

“…Key to SuFEx activation is the requirement for fluoride to transit from a strong covalent bond to a leaving group-a process mediated by 3° amine derived catalysts [8] and thought to involve bifluoride ion and related species. [7,[9][10][11][12][13] Early in the development of SuFEx, we identified sulfuryl fluoride (SO 2 F 2 ) [7,14] as a sulfur(VI) hub for creating diaryl sulfate links between molecules. Under SuFEx conditions the latent reactivity of the otherwise stable S VI -F bond is roused to react with SuFExable substrates.…”