Specific and Chemoselective Multi-α-arylation Reaction of Benzoylformic Acid with or without Decarbonylation in P<sub>2</sub>O<sub>5</sub>−MsOH and Related Acidic Media
P(2)O(5)-MsOH, or relatedacidicmedia, benzoylformic acid (1) undergoes three types of di- or mono-alpha-arylation reactions with or without decarbonylation ((1) decarbonylative alpha, alpha-diarylation, yielding triarylmethanols 6, (2) decarbonylative alpha-monoarylation, giving benzophenone derivatives 7, and (3) alpha,alpha-diarylation without decarbonylation, affording diarylated carboxylic acids 5) and