SuFEx (Sulfur Fluoride Exchange) is a modular, next generation family of click reactions, geared towards the rapid and reliable assembly of functional molecules.

Specific interactions between proteins and their binding partners are fundamental to life processes. The ability to detect protein complexes, and map their sites of binding, is crucial to understanding basic biology at the molecular level. Methods that employ sensitive analytical techniques such as mass spectrometry have the potential to provide valuable insights with very little material and on short time scales. Here we present a differential protein footprinting technique employing an efficient photo-activated probe for use with mass spectrometry. Using this methodology the location of a carbohydrate substrate was accurately mapped to the binding cleft of lysozyme, and in a more complex example, the interactions between a 100 kDa, multi-domain deubiquitinating enzyme, USP5 and a diubiquitin substrate were located to different functional domains. The much improved properties of this probe make carbene footprinting a viable method for rapid and accurate identification of protein binding sites utilizing benign, near-UV photoactivation.

Diversity Oriented Clicking (DOC) is a unified click‐approach for the modular synthesis of lead‐like structures through application of the wide family of click transformations. DOC evolved from the concept of achieving “diversity with ease”, by combining classic C−C π‐bond click chemistry with recent developments in connective SuFEx‐technologies. We showcase 2‐Substituted‐Alkynyl‐1‐Sulfonyl Fluorides (SASFs) as a new class of connective hub in concert with a diverse selection of click‐cycloaddition processes. Through the selective DOC of SASFs with a range of dipoles and cyclic dienes, we report a diverse click‐library of 173 unique functional molecules in minimal synthetic steps. The SuFExable library comprises 10 discrete heterocyclic core structures derived from 1,3‐ and 1,5‐dipoles; while reaction with cyclic dienes yields several three‐dimensional bicyclic Diels–Alder adducts. Growing the library to 278 discrete compounds through late‐stage modification was made possible through SuFEx click derivatization of the pendant sulfonyl fluoride group in 96 well‐plates—demonstrating the versatility of the DOC approach for the rapid synthesis of diverse functional structures. Screening for function against MRSA (USA300) revealed several lead hits with improved activity over methicillin.

SuFEx click chemistry is a powerful method designed for the selective, rapid, and modular synthesis of functional molecules. Classical SuFEx reactions form stable S−O linkages upon exchange of S−F bonds with aryl silyl‐ether substrates, and while near‐perfect in their outcome, are sometimes disadvantaged by relatively high catalyst loadings and prolonged reaction times. We herein report the development of accelerated SuFEx click chemistry (ASCC), an improved SuFEx method for the efficient and catalytic coupling of aryl and alkyl alcohols with a range of SuFExable hubs. We demonstrate Barton's hindered guanidine base (2‐tert‐butyl‐1,1,3,3‐tetramethylguanidine; BTMG) as a superb SuFEx catalyst that, when used in synergy with silicon additive hexamethyldisilazane (HMDS), yields stable S−O bond linkages in a single step; often within minutes. The powerful combination of BTMG and HMDS reagents allows for catalyst loadings as low as 1.0 mol % and, in congruence with click‐principles, provides a scalable method that is safe, efficient, and practical for modular synthesis. ASSC expands the number of accessible SuFEx products and will find significant application in organic synthesis, medicinal chemistry, chemical biology, and materials science.

We demonstrate 1,2-dibromoethane-1-sulfonyl fluoride (DESF) as a bench-stable and readily accessible precursor to the robust SuFEx connector, 1-bromoethene-1-sulfonyl fluoride (BESF). The in situ generation of BESF from DESF opens up several new reaction profiles, including application in the syntheses of unprecedented 3-substituted isoxazole-5-sulfonyl fluorides, 1-substituted-1H-1,2,3-triazole-4-sulfonyl fluorides, 2-amino-1-bromoethane-1-sulfonyl fluorides and 4-bromo-β-sultams in good to excellent yields. These new modules comprise a pendant sulfonyl fluoride handle, which further undergoes facile and selective SuFEx reactions with a selection of aryl silyl ethers to generate stable and useful sulfonate connections.

Mapping the interaction sites between membrane-spanning proteins is a key challenge in structural biology. In this study a carbene-footprinting approach was developed and applied to identify the interfacial sites of a trimeric, integral membrane protein, OmpF, solubilised in micelles. The diazirine-based footprinting probe is effectively sequestered by, and incorporated into, the micelles, thus leading to efficient labelling of the membrane-spanning regions of the protein upon irradiation at 349 nm. Areas associated with protein-protein interactions between the trimer subunits remained unlabelled, thus revealing their location.

Modular polyketide synthases (PKSs) produce numerous structurally complex natural products that have diverse applications in medicine and agriculture. PKSs typically consist of several multienzyme subunits that utilize structurally defined docking domains (DDs) at their N and C termini to ensure correct assembly into functional multiprotein complexes. Here we report a fundamentally different mechanism for subunit assembly in trans-acyltransferase (trans-AT) modular PKSs at the junction between ketosynthase (KS) and dehydratase (DH) domains. This mechanism involves direct interaction of a largely unstructured docking domain (DD) at the C terminus of the KS with the surface of the downstream DH. Acyl transfer assays and mechanism-based crosslinking established that the DD is required for the KS to communicate with the acyl carrier protein appended to the DH. Two distinct regions for binding of the DD to the DH were identified using NMR spectroscopy, carbene footprinting, and mutagenesis, providing a foundation for future elucidation of the molecular basis for interaction specificity.

Mapping the interaction sites between membrane‐spanning proteins is a key challenge in structural biology. In this study a carbene‐footprinting approach was developed and applied to identify the interfacial sites of a trimeric, integral membrane protein, OmpF, solubilised in micelles. The diazirine‐based footprinting probe is effectively sequestered by, and incorporated into, the micelles, thus leading to efficient labelling of the membrane‐spanning regions of the protein upon irradiation at 349 nm. Areas associated with protein–protein interactions between the trimer subunits remained unlabelled, thus revealing their location.