In this review, we highlight the use of organic photoredox catalysts in a myriad of synthetic transformations with a range of applications. This overview is arranged by catalyst class where the photophysics and electrochemical characteristics of each is discussed to underscore the differences and advantages to each type of single electron redox agent. We highlight both net reductive and oxidative as well as redox neutral transformations that can be accomplished using purely organic photoredox-active catalysts. An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.

Organic Photoredox Catalysis

N-Heterocyclic Carbenes in Late Transition Metal Catalysis

Asymmetric enamine catalysis.

Reactions that convert carbon–hydrogen (C–H) bonds into carbon–carbon (C–C) or carbon–heteroatom (C–Y) bonds are attractive tools for organic chemists, potentially expediting the synthesis of target molecules through new disconnections in retrosynthetic analysis. Despite extensive inorganic and organometallic study of the insertion of homogeneous metal species into unactivated C–H bonds, practical applications of this technology in organic chemistry are still rare. Only in the past decade have metal-catalyzed C–H functionalization reactions become more widely utilized in organic synthesis.Research in the area of homogeneous transition metal–catalyzed C–H functionalization can be broadly grouped into two subfields. They reflect different approaches and goals and thus have different challenges and opportunities. One approach involves reactions of completely unfunctionalized aromatic and aliphatic hydrocarbons, which we refer to as “first functionalization”. Here the substrates are nonpolar and hydrophobic a...

Weak coordination as a powerful means for developing broadly useful C-H functionalization reactions.

Small-molecule H-bond donors in asymmetric catalysis.

Nickel-catalyzed regioselective allylation of allylic alcohols

A new preparative method for various metal enolates

A variety of aluminum (aryloxide)s were used with triphenylmethyl fluoride (TrF) initiator for the isoselective cationic polymerization of t-butyl vinyl ether. This contribution discusses the relationship between polymer tacticity and counteranion structure, which changed according to the bulkiness, strength and chirality of the Lewis acid combined with TrF so as to make the ionic pair more interactive in the polymerization process. Newly developed organoaluminum activators, 15 and 22, showed mm = 55–57%, which is a more than 10% increase in mm compared with achiral aluminum compounds.

Polymerization of t-Butyl Vinyl Ether Mediated by an Aluminum Lewis Acid-TrF System and Its Complex Structure-Tacticity Correlation.

Metal ion-exchanged montmorillonites were found to be efficient catalysts for the condensation reaction of trimethylhydroquinone with isophytol to afford α-tocopherol in high yield. The condensation reaction proceeded smoothly using 50 w/w% of catalyst in various solvents. The catalyst was easily recovered by filtration of the reaction mixture after the reaction was completed, and could be reused.

Hisashi Yamamoto

Papers

Nickel-catalyzed regioselective allylation of allylic alcohols

A new preparative method for various metal enolates

Polymerization of t-Butyl Vinyl Ether Mediated by an Aluminum Lewis Acid-TrF System and Its Complex Structure-Tacticity Correlation.

Metal Ion-Exchanged Montmorillonites as Practical and Useful Solid Catalysts for the Synthesis of α-Tocopherol

Pyrolysis of benzenediazonium bis(trifluoromethanesulfonyl)methide