Direct evidence of a radical mechanism in the addition reaction of iododifluoroesters to olefins by spin trapping

Visible-Light-Driven Bisfunctionalization of Unactivated Olefins via the Merger of Proton-Coupled Electron Transfer and Carbene Catalysis

Herein, we reported an N-heterocyclic carbene (NHC) and photo-co-catalyzed alkylacylation of olefins in the presence of the versatile synthon diazo ester, providing a new idea for transient radical generation with the only byproduct being N₂. Particularly, this radical process employs traditional carbene precursor diazo esters as the radical source, which is the first case in NHC catalysis. Compared to the previous pathway that produces radicals with large discard fragments, this merged channel possesses great atom economy.

Palladium-catalyzed reductive cross-coupling between α-bromo carboxamides and terminal alkynes

A Pd-catalyzed reductive cross-coupling between α-bromo carboxamides and terminal alkynes was developed featuring a radical pathway and distinct from the Sonogashira coupling.

Me(2)Zn as a radical source in Reformatsky-type reactions

Experimental evidence for the generation of radicals by Me(2)Zn used in Reformatsky reactions was unequivocally established with a radical trap.

A study of free radical release from β-cyclodextrin-anticancer pro-drugs adducts in water

A novel approach in cancer chemotherapy concerns the attempt to employ radical affording substances (RAS) as pro-drugs able to produce irreversible damages on the tumor cell, so stimulating cellular apoptosis. However, radical species can react quickly towards the chemical environment into which they have been generated before reaching their proper sites of action, i.e. the tumor cells. We recently started a study aiming to accomplish new therapeutic systems for the transport of RAS in biological medium. In this paper we report the effect of stabilization produced by beta-cyclodextrin on carbon centered radicals afforded by some mercaptopyridine congeners which have already been shown to possess strong anticancer activity in vitro. EPR experiments carried out on aqueous solutions of N-acyloxy-pyridinethione analogues like 1 (R = adamantyl, cyclohexyl) in the presence of beta-cyclodextrin, demonstrated that photochemically produced alkyl radicals are involved in an adduct with beta-cyclodextrin which works as a cage preventing the interaction of such radicals with the medium. Furthermore, the presence of beta-cyclodextrin has been shown to delay the generation of radicals in water due to a possible interaction between the cyclodextrin cavity and the mercaptopyridine moiety of 1 which is the part of the molecule responsible for beginning the radical event.