Nickel-Catalyzed Amination of Alkyl Electrophiles.

Bimolecular nucleophilic substitution SN2 is the earliest and most important means of amination of alkyl electrophiles; its practical utilization is largely limited to primary or activated substrates. Furthermore, a persistent challenge lies in establishing C(sp3)-N bonds from alkyl substrates in cross-coupling chemistry using palladium and nickel catalysts. Therefore, the methods of constructing C(sp3)-N bonds remain rare from alkyl electrophiles. The existing routes are limited to copper catalysis and photoredox catalysis. Here, we demonstrate an alternative amination strategy for rapid construction of C(sp3)-N bonds from accessible alkyl electrophiles, which were used as radical precursors under nickel catalysis by Ni (III) species reductive eliminations in high efficiency.

Photoredox Microfluidic Synthesis of Trifluoromethylated Amino Acids.

Fluorinated amino acids are a class of highly valuable building blocks that are widely employed in biological science and pharmaceutical industry for improved stability, activity, and folding property of proteins. However, the synthetic approach has conventionally been constrained by harsh conditions and limited substrate range. We demonstrate a general synthetic protocol for photoinduced α-CF3 amino acids using continuous flow technology that benefits from enhanced fusion and precise control of reaction time, making it potentially useful in large-scale peptide synthesis.

Radical boron migration of allylboronic esters.

A photocatalyzed 1,3-boron shift of allylboronic esters is reported. The boron atom migration through the allylic carbon skeleton proceeds via consecutive 1,2-boron migrations and Smiles-type rearrangement to furnish a variety of terminally functionalized alkyl boronates. Several types of migrating variations of heteronuclei radicals and dearomatization processes are also tolerated, allowing for further elaboration of highly functionalized boron-containing frameworks.

Electrochemical C-N bond activation for deaminative reductive coupling of Katritzky salts.

Electrosynthesis has received great attention among researchers in both academia and industry as an ideal technique to promote single electron reduction without the use of expensive catalysts. In this work, we report the electrochemical reduction of Katritzky salts to alkyl radicals by sacrificing the easily accessible metal anode. This catalyst and electrolyte free platform has broad applicability to single electron transfer chemistry, including fluoroalkenylation, alkynylation and thiolation. The deaminative functionalization is facilitated by the rapid molecular diffusion across microfluidic channels, demonstrating the practicality that outpaces the conventional electrochemistry setups.

Electrochemical Oxidative Esterification of Thiophenols: Efficient Access to Sulfinic Esters.

BACKGROUND: The sulfinic esters are important and useful building blocks in organic synthesis. OBJECTIVE: The aim of this study was to develop a simple and efficient method for the synthesis of sulfinic esters. MATERIALS AND METHODS: Constant current electrolysis from thiols and alcohols was selected as the method for the synthesis of sulfinic esters. RESULTS AND DISCUSSION: A novel electrochemical method for the synthesis of sulfinic esters from thiophenols and alcohols has been developed. Up to 27 examples of sulfinic esters have been synthesized using the current methods. This protocol shows good functional group tolerance as well as high efficiency. In addition, this protocol can be easily scaled up with good efficiency. Notably, heterocycle-containing substrates, including pyridine, thiophene, and benzothiazole, gave the desired products in good yields. A plausible reaction mechanism is proposed. CONCLUSION: This research not only provides a green and efficient method for the synthesis of sulfinic esters but also shows new applications of electrochemistry in organic synthesis. It is considered that this green and efficient synthetic protocol used to prepare sulfinic esters will have good applications in the future.

Electrochemical synthesis of 1,2-diketones from alkynes under transition-metal-catalyst-free conditions.

We report an electrochemical protocol for the direct oxidation of internal alkynes in air to provide 1,2-diketones. A variety of functional groups and heterocycle-containing substrates can be tolerated well under mild conditions.

Electrochemical C-O Bond Formation: Facile Access to Aromatic Lactones.

An efficient and robust methodology based on electrochemical techniques for the direct synthesis of aromatic lactones through dehydrogenative C-O cyclization is described. This new and useful electrochemical reaction can tolerate a variety of functional groups, and is scalable to 100 g under mild conditions. Remarkably, heterocycle-containing substrates can be employed, thus expanding the scope of radical C-O cyclization reactions.