Only oxygen and acid! The oxidative coupling of xanthene and other activated benzylic compounds with carbon nucleophiles such as ketones, can be performed under ambient conditions without solvent by simply using oxygen and catalytic amounts of methanesulfonic acid. The proposed reaction mechanism involves substrate activation by formation of hydroperoxides; the method can therefore be regarded as an
A novel coupling reaction of diaryl methanols with ketones or aldehydes has been developed under the catalysis of AlCl3. Various ketones and aldehydes could couple with 9H‐xanthen‐9‐ol smoothly, affording coupling products in 48% –88% yields. A plausible mechanism using AlCl3 to activate both diaryl methanol and ketone or aldehyde is proposed.