A Direct Synthesis of Symmetrical (E,E)-1,4-Diaryl-1,3-butadienes by Wenkert Arylation of Thiophene

Fiaud's Acid: A Brønsted Acid Catalyst for Enantioselective Friedel-Crafts Alkylation of Indoles with 2-Alkene-1,4-diones

Fiaud's acid (trans-1-hydroxy-2,5-diphenylphospholane 1-oxide), a phospholane-based phosphinic acid, is introduced as an efficient chiral Brønsted acid catalyst that mediates the asymmetric Friedel-Crafts alkylation of indoles with 2-butene-1,4-diones. With a catalyst loading of 10 mol %, the reaction proceeded smoothly to afford 2-(indol-3-yl)butane-1,4-diones in high yield (up to 82%) and high enantioselectivity (up to 91% ee, one such product showed enhanced ee of 98% after recrystallization). The reaction conditions are sufficiently mild to tolerate sensitive functionality at room temperature and are therefore suitable for the synthesis of complex targets.

Synthesis of PEG-supported organotrifluoroborates and their applications in palladium-catalyzed homo-coupling reactions

A general synthetic route to water-soluble PEG-supported organotrifluoroborates has been developed. In the presence of air and catalytic amounts of Pd(OAc)₂, the PEG-supported organotrifluoroborates undergo homo-coupling reactions smoothly at room temperature.

Ni-catalyzed stereoselective arylation of inert C-O bonds at low temperatures

A Ni-catalyzed arylation of inert C-O bonds that operates at temperatures as low as -40 °C is described. Unlike other methods for C-O bond cleavage utilizing organometallic species, this protocol operates at low temperatures, thus allowing the presence of sensitive functional groups with exquisite site-selectivity and stereoselectivity.