Given its many distinct characteristics, electrochemistry represents an attractive approach to meet the prevailing trends in organic synthesis. In particular, electrocatalysis—a process that integrates electrochemistry and small-molecule catalysis—has the potential to substantially improve the scope of synthetic electrochemistry and provide a wide range of useful transformations. Recently, we have demonstrated new catalytic approaches that combine electrochemistry and redox-metal catalysis for the oxidative difunctionalization of alkenes to access a diverse array of vicinally functionalized structures. This Perspective details our design principles underpinning the development of electrochemical diazidation, dichlorination, and halotrifluoromethylation of alkenes, which were built on foundational work by others in the areas of synthetic electrochemistry, radical chemistry, and transition-metal catalysis. The introduction of redox-active Mn catalysts allows the generation of radical intermediates from read...

An Electrocatalytic Approach to the Radical Difunctionalization of Alkenes

Synthetic aspects of diels-alder cycloadditions with heterodienophiles

We report a Mn-catalyzed electrochemical dichlorination of alkenes with MgCl2 as the chlorine source. This method provides operationally simple, sustainable, and efficient access to a variety of vicinally dichlorinated compounds. In particular, alkenes with oxidatively labile functional groups, such as alcohols, aldehydes, sulfides, and amines, were transformed into the desired vicinal dichlorides with high chemoselectivity. Mechanistic data are consistent with metal-mediated Cl atom transfer as the predominant pathway enabling dual C–Cl bond formation and contradict an alternative pathway involving electrochemical evolution of chlorine gas followed by Cl2-mediated electrophilic dichlorination.

Electrocatalytic Radical Dichlorination of Alkenes with Nucleophilic Chlorine Sources

Direct Oxidative Allylic and Vinylic Amination of Alkenes through Selenium Catalysis Bringing “N” into the game: The direct chemoselective nitrogenation of unactivated alkenes can be achieved through oxidative selenium catalysis (see scheme). This protocol provides a broad variety of allylic imides in yields of up to 89 % using N-fluorobenzenesulfonimide (NFSI) as the terminal oxidant and nitrogen source. Furthermore, an unprecedented selenium-catalyzed vinylic C(sp)–H nitrogenation was discovered. Angewandte Chemie

Direct Oxidative Allylic and Vinylic Amination of Alkenes through Selenium Catalysis

A systematic investigation into the Lewis base catalyzed, asymmetric, intramolecular selenoetherification of olefins is described. A critical challenge for the development of this process was the identification and suppression of racemization pathways available to arylseleniranium ion intermediates. This report details a thorough study of the influences of the steric and electronic modulation of the arylselenenyl group on the configurational stability of enantioenriched seleniranium ions. These studies show that the 2-nitrophenyl group attached to the selenium atom significantly attenuates the racemization of seleniranium ions. A variety of achiral Lewis bases catalyze the intramolecular selenoetherification of alkenes using N-(2-nitrophenylselenenyl)succinimide as the electrophile along with a Bronsted acid. Preliminary mechanistic studies suggest the intermediacy of ionic Lewis base-selenium(II) adducts. Most importantly, a broad survey of chiral Lewis bases revealed that 1,1'-binaphthalene-2,2'-diamine (BINAM)-derived thiophosphoramides catalyze the cyclization of unsaturated alcohols in the presence of N-(2-nitrophenylselenenyl)succinimide and methanesulfonic acid. A variety of cyclic seleno ethers were produced in good chemical yields and in moderate to good enantioselectivities, which constitutes the first catalytic, enantioselective selenofunctionalization of unactivated olefins.

Preparative and Mechanistic Studies Toward the Rational Development of Catalytic, Enantioselective Selenoetherification Reactions

Conversion of allylic phenylselenides to the rearranged allylic chlorides by N-chlorosuccinimide. Mechanism of selenium-catalyzed allylic chlorination of .beta.-pinene

Tetsuo Hori

Papers

Conversion of allylic phenylselenides to the rearranged allylic chlorides by N-chlorosuccinimide. Mechanism of selenium-catalyzed allylic chlorination of .beta.-pinene

Selenium-catalyzed nonradical chlorination of olefins with N-chlorosuccinimide

Allylic deuteration and tritiation of olefins with N-sulfinylsulfonamides