No abstract

Electron-transfer photocatalysis provides access to the elusive and unprecedented N-pyridyl radical cation from selected N-substituted pyridinium reagents.T he resulting C(sp 2 )ÀHf unctionalization of (hetero)arenes furnishes versatile intermediates for the development of valuable aminated aryl scaffolds.M echanistic studies that include the first spectroscopic evidence of as pin-trapped N-pyridyl radical adduct implicate SET-triggered, pseudo-mesolytic cleavage of the N À Xp yridinium reagents mediated by visible light.

A total synthesis of (-)-rhazinilam and formal syntheses of (+)-eburenine and (+)-aspidospermidine that rely on a copper(I)-catalyzed asymmetric propargylic substitution as the key step are reported. A salient feature of the reaction is the asymmetric construction of a quaternary stereocenter in high yield and enantiomeric excess.

A systematic study of the opening of a collection of chlorinated vinyl epoxides is reported, which includes experiments that implicate both five- and four-membered chloronium ions as plausible intermediates in this type of epoxide opening reaction.

Electron‐transfer photocatalysis provides access to the elusive and unprecedented N‐pyridyl radical cation from selected N‐substituted pyridinium reagents. The resulting C(sp2)−H functionalization of (hetero)arenes furnishes versatile intermediates for the development of valuable aminated aryl scaffolds. Mechanistic studies that include the first spectroscopic evidence of a spin‐trapped N‐pyridyl radical adduct implicate SET‐triggered, pseudo‐mesolytic cleavage of the N−X pyridinium reagents mediated by visible light.