The conversion of olefin feedstocks to architecturally complex alkanes represents an important strategy in the expedient generation of valuable molecules for the chemical and life sciences. Synthetic approaches are reliant on the electrophilic activation of unactivated olefins, necessitating functionalization with nucleophiles. However, the reductive functionalization of unactivated and less activated olefins with electrophiles remains an ongoing challenge in synthetic chemistry. Here, we report the nucleophilic activation of inert styrenes through a photoinduced direct single electron reduction to the corresponding nucleophilic radical anion. Central to this approach is the multiphoton tandem photoredox cycle of the iridium photocatalyst [Ir(ppy) 2 (dtbbpy)]PF 6 , which triggers in situ formation of a high-energy photoreductant that selectively reduces styrene olefinic π bonds to radical anions without stoichiometric reductants or dissolving metals. This mild strategy enables the chemoselective reduction and hydrofunctionalization of styrenes to furnish valuable alkane and tertiary alcohol derivatives. Mechanistic studies support the formation of a styrene olefinic radical anion intermediate and a Birch-type reduction involving two sequential single electron transfers. Overall, this complementary mode of olefin activation achieves the hydrofunctionalization of less activated alkenes with electrophiles, adding value to abundant olefins as valuable building blocks in modern synthetic protocols.

Visible light irradiation of 8-aminoquinoline Pd(ii) complexes initiates photoinduced electron transfer with alkyl halides, affording C–H halogenation over C–C bond adducts. A method for inert C(sp3)–H bond halogenation (Br, Cl and I) is reported.

A methodology for a radical Pictet–Spengler reaction promoted by visible light photoredox catalysis is described. This strategy furnishes tetrahydroisoquinoline derivatives bearing electron poor and electron rich substituents. The reaction proceeds at room temperature and with excellent regioselectivity for the 6-endo intramolecular cyclisation. This radical approach provides a complementary method for the synthesis of the tetrahydroisoquinoline scaffold with substitution patterns inaccessible via established thermal transformations.

<p><a></a>Herein we report a visible light multiphoton tandem photoredox catalysis strategy enabling a distinctive mode of olefin activation via a one electron reduction to the corresponding radical anion. This highly nucleophilic intermediate was harnessed to develop a method for the formal hydrogenation of unactivated alkenes under mild reaction conditions, in the absence of hydrogen gas or dissolving metals. <b></b></p>

<p><a></a>Herein we report a visible light multiphoton tandem photoredox catalysis strategy enabling a distinctive mode of olefin activation via a one electron reduction to the corresponding radical anion. This highly nucleophilic intermediate was harnessed to develop a method for the formal hydrogenation of unactivated alkenes under mild reaction conditions, in the absence of hydrogen gas or dissolving metals. <b></b></p>