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The direct 1,6-nucleophilic difluoromethylation, trifluoromethylation, and difluoroalkylation of para-quinone methides (p-QMs) with Me3SiRf (Rf = CF2H, CF3, CF2CF3, CF2COOEt, and CF2SPh) under mild conditions are described. Although Me3SiCF2H shows lower reactivity than Me3SiCF3, it can react with p-QMs promoted by CsF/18-Crown-6 to give structurally diverse difluoromethyl products in good yields. The products can then be further converted into fluoroalkylated para-quinone methides and α-fluoroalkylated diarylmethanes. [ABSTRACT FROM AUTHOR]

A new method of constructing "ArSCF2CF2Cu" from ArSCu and TMSCF2Br (TMS=trimethylsilyl) has been developed. The cross‐coupling reactions of the obtained "ArSCF2CF2Cu" with diverse aryl iodides (Ar′I) provide an efficient access to Ar′CF2CF2SAr. Mechanistic studies demonstrate that the "ArSCF2CF2Cu" species were generated through controllable double difluoromethylene insertions into ArS−Cu bonds rather than the 1,2‐addition of ArSCu to tetrafluoroethylene. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The electrophilic addition to an alkene with an electrophile has been widely studied and applied in organic synthesis. The organic chemistry textbook describes the classical reaction between an alkene and an iodine electrophile (such as elemental iodine and N‐iodosuccinimide (NIS)) as a typical ionic reaction, in which an iodonium ion is formed and then attacked by a nucleophile. However, in this article, we report a new and unusual reaction mode between an alkene and NIS; that is, a single electron transfer (SET) process occurs between these two reactants by forming an electron‐donor acceptor complex. Not only does this unusual single electron transfer reaction between an alkene and NIS add fundamentally important knowledge to organic chemistry, it also provides a valuable synthetic method as the new SET reaction mode with opposite regioselectivity as compared with the traditional ionic mode. [ABSTRACT FROM AUTHOR]

We have developed a new strategy for controllable single and double difluoromethylene (CF2) formal insertions into C−H bonds of aldehydes with nearly full selectivity under transition‐metal‐free conditions. The key to the success of controllable CF2 insertions lies in the well‐defined formation of 2,2‐difluoroenolsilyl ether and 2,2,3,3‐tetrafluorocyclopropanolsilyl ether intermediates using difluorocarbene reagent TMSCF2Br (TMS=trimethylsilyl). These two intermediates can react with various electrophiles including proton sources and various halogenation reagents, allowing for the access to diverse arrays of ketones containing difluoromethylene (CF2) and tetrafluoroethylene (CF2CF2) units. The first synthesis of relatively stable 2,2,3,3‐tetrafluorocyclopropanolsilyl ethers has been achieved, which offers a new platform to explore other unknown chemical space. [ABSTRACT FROM AUTHOR]