Photoacid Catalyzed Reaction of Phenol with Styrene

Abstract

ABSTRACT:The reaction of styrene with phenol using photoacid catalyst has been investigated. Upon irradiation with 450 nm light, protonated merocyanine photoacid converts into spiropyran form with releasing proton. The reaction of styrene with phenol has been conducted under irradiation with 450 nm light using merocyanine photoacid catalyst at room temperature in comparison with the results using some selected catalysts including H 2 SO 4 or FeCl 3 at the reaction temperature of 120 o C.Sterically hindered phenols are effective inhibitors of free-radical processes and light stabilizers.

Photoacid-Enabled Synthesis of Indanes via Formal [3 + 2] Cycloaddition of Benzyl Alcohols with Olefins

“…Lei’s and Kokotos’s group reported that 2 or eosin Y 3 could catalyze the acetalization reaction (Scheme c). , Wang’s group discovered a stereoselective synthesis of 2-deoxyglycosides from glycals using 3 and diphenyl disulfide as the catalyst (Scheme d) . Regardless of these impressive achievements, the excited-state proton transfer (ESPT) photoacid catalysts are still challenging to provoke many acid-catalyzed reactions because the free protons of the ESPTs could recombine very fast with the corresponding conjugated bases in the ground state (Scheme e) . To achieve a significant increase in the proton concentration under visible light irradiation, metastable-state photoacids such as MEH were discovered and thrived (Scheme f) .…”