Strain‐Promoted Cycloaddition of Cyclopropenes with o‐Quinones: A Rapid Click Reaction

Abstract

Novel click reactions are of continued interest in fields as diverse as bio‐conjugation, polymer science and surface chemistry. Qualification as a proper “click” reaction requires stringent criteria, including fast kinetics and high conversion, to be met. Herein, we report a novel strain‐promoted cycloaddition between cyclopropenes and o‐quinones in solution and on a surface. We demonstrate the “click character” of the reaction in solution and on surfaces for both monolayer and polymer brush functionalization.

Recent Progress in the Development of Composite Membranes Based on Polybenzimidazole for High Temperature Proton Exchange Membrane (PEM) Fuel Cell Applications

“…Chemical modification of PBI by means of click chemistry reactions [ 90 ] and by the alternative and enviromental friendly metal-free click chemistry reactions [ 91 ], such as the strain-promoted azide–alkyne cycloaddition (SPAAC) [ 92 ], the thiol-ene [ 93 , 94 ] and thiol-yne coupling [ 95 , 96 ], the inverse electron−demand Diels−Alder (IEDDA) reaction [ 97 ], the strain-promoted alkyne−nitrone cycloaddition (SPANC) [ 98 , 99 ], and the strain-promoted oxidation-controlled cyclooctyne–1,2–quinone cycloaddition (SPOCQ) [ 100 , 101 , 102 ], can afford an interesting variety of PBI structures with potential applications in PEM for fuel cell applications. The main advantages of these reactions include their fast reaction kinetics, versatililty and regiospecificity, high product yields, and easy purification of the products.…”

Silicon‐Free SuFEx Reactions of Sulfonimidoyl Fluorides: Scope, Enantioselectivity, and Mechanism

“…Click chemistry has been widely used to construct functional molecular skeletons concisely and efficiently . A variety of new click reactions has been developed, such as CuI‐catalyzed azide–alkyne cycloadditions (CuAAC) as well as metal‐free click reactions such as thiol–ene, oxime ligation, (thio‐)Michael, Diels–Alder, strain‐promoted cycloadditions between azide–alkyne (SPAAC), cyclo‐octyne‐ o ‐quinone (SPOCQ), and cyclopropene‐ o ‐quinone reactions. More recently, the pioneering work of Gembus and Sharpless revived the sulfur(VI) fluoride exchange (SuFEx) reaction from “old‐school chemistry” to the latest generation of click reactions.…”

Orthogonal, dual protein labelling by tandem cycloaddition of strained alkenes and alkynes to ortho-quinones and azides

“…Apparently, the fused cyclopropane ring increases the rate approximately 300-fold, in analogy with enhancement of reaction rate with tetrazine. 18 For comparison, cpTCO-SPOCQ is more than 10 3 times faster than reaction of quinone 1 with a cyclopropene (o1.7-1.9 M À1 s À1 ) 22 and strainpromoted cycloadditions involving azides (0.01-1 M À1 s À1 ), 7 however slightly slower than SPIEDAC reaction of regular TCO with tetrazines (2000 to 45000 M À1 s À1 ), 13 and much slower than the fastest known cpTCO-tetrazine ligations (reaching above 10 6 M À1 s À1 ). 23 Nevertheless, in contrast to azide and tetrazine, an ortho-quinone is readily generated from a canonical amino acid (tyrosine), and therefore has the inherent advantage of (inducible) bioconjugation chemistry to native proteins.…”