A metal- and reagent-free, electrochemical intramolecular oxidative amination reaction of tri- and tetrasubstituted alkenes has been developed. The electrosynthetic method proceeds through radical cyclization to form the key C-N bond, allowing a variety of hindered tri- and tetrasubstituted olefins to participate in the amination reaction. The result is the efficient synthesis of a host of alkene-bearing cyclic carbamates and ureas and lactams.

An unprecedented radical difluoromethylarylation reaction of alkynes has been developed by discovering a new difluoromethylation reagent, CFHSONHNHBoc. This air-stable and solid reagent can be prepared in one step from commercially available reagents CFHSOCl and NHNHBoc. The CFH radical, generated through ferrocene-mediated electrochemical oxidation, participates in an unexplored alkyne addition reaction followed by a challenging 7-membered ring-forming homolytic aromatic substitution step to afford fluorinated dibenzazepines.

Electrochemical 1,2‐hydroxydifluoromethylation and C−H difluoromethylation of acrylamides were developed by using CF2HSO2NHNHBoc as the source of the CF2H group. These electricity‐powered oxidative alkene functionalization reactions do not need transition‐metal catalysts or chemical oxidants. The reaction outcome, 1,2‐difuntionalization or C−H functionalization, is determined by the substituents on the amide nitrogen atom of the acrylamides instead of by the reaction conditions.

What is the most favorite and original chemistry developed in your research group?The visible light photosensitizer DPZ. How did you get into this specific field? Could you please share some experiences with our readers?Since I began my postdoctoral work at NUS, chiral hydrogen-bonding catalysis, an important branch of asymmetric organocatalysis, has become the general area of focus of my research. To broaden the applications of this strategy, I proposed to exploit photocatalysis to generate highly reactive radical intermediates, thus overcoming the current limitations in both reaction and substrate types stemming from the low energy of hydrogen-bonding interactions. The development of highly efficient organophotocatalysts and explorations of transition metal-free cooperative photocatalysis and chiral hydrogen-bonding catalysis have therefore been my research focus since 2013. My students and I strive to follow the saying "stick to the research direction, thoroughly understand the scientific challenges, and face those challenges with optimism and determination". What is the most important personality for scientific research?To do independent, original, ground-breaking and useful chemistry. What are your hobbies?Playing basketball, slow long distance running and reading. How do you maintain a balance between research and family?Having the understanding and support of my family is the most important thing since scientific research requires a large investment of time. Who influences you the most in your life?My parents.

An electrochemical hydropyridylation of thioesteractivated alkenes with 4-cyanopyridines has been developed. The reactions experience a tandem electroreduction of both substrates on the cathode surface, protonation, and radical cross-coupling process, resulting in a variety of valuable pyridine variants, which contain a tertiary and even a quaternary carbon at the α-position of pyridines, in high yields. The employment of thioesters to the conjugated alkenes enables no requirement of catalyst and high temperature, representing a highly sustainable synthetic method. P yridine-containing compounds play an important role in natural products and drug candidates. 1−3 Hydropyridylation, which is the straightforward incorporation of a pyridyl group onto alkenes, 4,5 has become an appealing strategy, given that the substrates are multitudinous and readily accessible and the produced alkylpyridines feature promising biological utilities. To date, hydrogen/halogen−metal exchange, 6 transition-metal catalysis, 7−9 and radical reaction 10−20 have been developed to accomplish such a significant chemical transformation (Scheme 1a). However, promoter, catalyst, or stoichiometric terminal reductant is indispensable to the reactions, resulting in poor atom economy, which should impede the exploitation of the methods in industry. Furthermore, all methods are limited to constructing a tertiary carbon α to pyridines.

An electrochemical method for the deoxygenation of N-heteroaromatic N-oxide to give the corresponding N-heteroaromatics has been developed. Several classes of N-heterocycles such as pyridine, quinoline, isoquinoline, and phenanthridine are tolerated. The electrochemical reactions proceed efficiently in aqueous solution without the need for transition-metal catalysts and waste-generating reducing reagents.

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