[Cu(dap)2]Cl effectively catalyzes azide addition from the Zhdankin reagent to styrene-type double bonds, and subsequent addition of a third component to the benzylic position. In the presence of light, a photoredox cycle is implicated with polar components such as methanol or bromide adding to a benzylic cation. In the absence of light, by contrast, double azidation takes place to give diazides. Therefore, regioselective double functionalization can be achieved in good to excellent yields, with a switch between light and dark controlling the degree of azidation.

An azidation method for C-N bond formation at benzylic C-H positions is described using copper-catalyzed visible light photochemistry and the Zhdankin azidoiodinane reagent. The method is applicable to a wide range of substrates bearing different functional groups and having a primary, secondary, or tertiary benzylic position, and is thought to proceed through a radical chain reaction.

A metal-free aminoarylation of internal alkynes is described, yielding tetrasubstituted enaminoates. The transformation proceeds in good to excellent yields through a tandem conjugate addition/Smiles rearrangement involving aryl and heteroaryl sulfonamides. Substrate scope is very broad under simple, user-friendly conditions, and the reaction can be used to easily access biologically active phenethylamine derivatives.

The diastereoselective addition of organozinc species to 1,2-anhydro sugars in toluene/n-dibutyl ether solvent is reported. Compared to the existing methods, the reaction proceeds at 0 °C, and only a slight excess of nucleophile is required to achieve good yields. Scope was assessed with different O-protected glycals along with various nucleophiles (aryl, alkynyl). This methodology was applied to the synthesis of the α-anomer of canagliflozin.

A range or electron-poor and heterocyclic sulfonamides react with phenylacetyl chlorides to produce benzhydryl derivatives in a single step. The reaction proceeds via tandem amide bond formation -Dohmori-Smiles rearrangement under simple conditions of aqueous base. In the case of o-nosylamides further reaction takes place at the nitro group to yield indazoles. Aryl and heteroaryl structures are fundamental to natural products and man-made molecules, and are frequently synthesized using stoichiometric organometallics and precious transition metal catalysts. These methods, while effective and hugely influential, are costly and environmentally unsustainable, making metal-free arylation methods 1 a key objective for future strategies in synthetic chemistry. We are interested in harnessing simple aryl sulfonamides as metal-free arylating agents in this regard, through the process set out in Scheme 1. The nitrogen atom acts as a nucleophilic trap for an electrophilic coupling partner, a benzyne in this example, generating an incipient carbanion (3) that triggers a 1,5-desulfonylative Smiles rearrangement. 2,3,4 Overall, the process repositions a cheap and readily available building block as both an arylating and aminating agent, critical transformations in the pharmaceutical industry, whilst proceeding without recourse to metal reagents.