NaS·9HO Enabled Defluorodisulfuration and Hydrodefluorination of Perfluorobutyl Tetralones: Synthesis of Trifluoromethyl 1,2-Dithioles.

An unprecedented defluorocyclization of perfluorobutyl tetralones with NaS·9HO was developed for the synthesis of trifluoromethyl 1,2-dithioles, which provided chemists novel access to biologically and pharmaceutically relevant organofluorides. Successive C(sp)-F bond functionalization at the perfluoroalkyl chain is vital for the formation of four C-H/C-S/S-S bonds and a five-membered S-heterocycle assembly. Cheap, weakly toxic, and odorless inorganic sulfide NaS·9HO acts as both a disulfurating precursor and a hydrodefluorinating reagent in this tandem multi-bond-interconverting reaction.

DMSO-Promoted Difluoroalkylation of Organophosphonium Salts with Difluoroenol Silyl Ethers.

An efficient method for the synthesis of β,β-di(hetero)aryl-α,α-difluorinated ketones using readily available organophosphonium salts and difluoroenol silyl ethers has been developed. This mild reaction features a good functional group tolerance, a scaled-up synthesis, and synthetic simplicity. By taking advantage of DMSO as a less-toxic promoter and solvent for the difluoroalkylation and C-P bond functionalization, the use of transition-metal catalysts and sensitive additives could be avoided.

Vitamin B1-catalyzed aerobic oxidative esterification of aromatic aldehydes with alcohols.

A straightforward aerobic oxidative esterification of aryl aldehydes with alcohols has been developed for the synthesis of substituted esters by employing vitamin B1 as a cost-effective, metal-free, and eco-friendly NHC catalyst. Air is used as a green terminal oxidant. The reaction is a useful addition to the existing NHC-catalytic oxidative esterification.

Regioselective synthesis of 6-nitroindole derivatives from enaminones and nitroaromatic compounds transition metal-free C-C and C-N bond formation.

Few methods are known for the synthesis of nitroindole derivatives. A simple and practical CsCO-promoted method for the synthesis of 6-nitroindole derivatives from enaminones and nitroaromatic compounds has been developed. Two new C-C and C-N bonds were formed in a highly regioselective manner under transition metal-free conditions.