UC Merced

Catalytic hydroarylation of alkenes is an attractive alternative to Friedel–Crafts type reactions of alkyl halides for the alkylative functionalization of aromatic C–H bonds. Many catalytic hydroarylations of alkenes are known, but few of them efficiently afford quaternary carbons from 1,1-disubstituted alkenes. Quaternary carbons are difficult to synthesize due to their sterically congested nature, which can lead to kinetic barriers to formation and thermodynamic instability. Herein, we report an efficient and highly selective methodology to intermolecularly functionalize trifluoromethylated (and other electron-deficient) α-methyl styrenes with a variety of aromatic compounds through the action of a tritylium precatalyst. This method gives access to a wide range of diaryl-dialkyl quaternary centers. Recent research into the reduction of alkene/alkyne to an alkane using B–B bond-containing reagents, such as B2(OH)4 and catalytic amounts of palladium on carbon, can mediate transition metal-catalyzed H atom transfer from H2O, leading to the reduction of alkenes and alkynes under mild conditions. Very few experiments for an introductory undergraduate organic chemistry lab demonstrate an alkene/alkyne to alkane reaction using transition metals. For this experiment, Palladium acetate was selected as the catalyst, an electron-rich alkene trans-stilbene was selected because of its ease to measure and to ensure the reaction could go to completion within the time constraints of a typical lab, which is 2-MeTHF was used as the solvent to increase the speed of completion of the reaction to an hour.