Novel Cerium(IV) ammonium nitrate induced dimerization of methoxystyrenes

Vanadium-Catalyzed Selective Oxidative Homocoupling of Alkenyl Phenols To Synthesize Lignan Analogs

“…To the best of our knowledge, no general method exists to catalytically and oxidatively homocouple terminal alkenyl phenols selectively. In 1997, it was reported that para -methoxy styrene could be homocoupled to give the quinone intermediate that was trapped with water to form a diaryl furan (β-β coupling) in modest yields using ceric ammonium nitrate (CAN) (Scheme .1) . In 2011, the oxidative enzyme laccase was studied with a simple styrene and was found to give a variety of oxidation products, including tetrahydrofuranyl and aryl ether scaffolds of interest, as a low yielding mixture (Scheme .2) .…”

“…In 1997, it was reported that para-methoxy styrene could be homocoupled to give the quinone intermediate that was trapped with water to form a diaryl furan (β-β coupling) in modest yields using ceric ammonium nitrate (CAN) (Scheme 1.1). 11 In 2011, the oxidative enzyme laccase was studied with a simple styrene and was found to give a variety of oxidation products, including tetrahydrofuranyl and aryl ether scaffolds of interest, as a low yielding mixture (Scheme 1.2). 12 In 2015, a method was reported to generate the aryl ether linkage (β-O coupling) seen in virolin.…”

TiO2 Photocatalytic Cyclization Reactions for the Syntheses of Aryltetralones

“…In the previous studies on the reactivities of styrene radical cations ,, and on the similar reactions carried out under homogeneous conditions, ,, 32 could be converted to 33 by loss of a proton, to the cation 34 by loss of a hydrogen-atom, and to 35 via loss of two protons and one electron . Then three pathways (Scheme ) are conceived herein for conversion of 32 to 3 .…”

Singlet Oxygen- and Hole-Mediated Selective Oxidation of Arylethylenes to Aryltetralones by Ag/Ag3PO4 under Visible Light Irradiation

“…Selective oxidation is a fundamental reaction toward many valuable fine chemicals. , The selective oxidation of arylethylenes to 4-aryltetralones, which involves oxidative coupling of two substrate molecules followed by oxygenation, is an important transformation due to the abundance of the substrates and the pharmaceutically active products analogous to natural lignans. − Although this cascade approach has been realized traditionally using stoichiometric oxidants and under relatively harsh conditions, − photocatalysis using molecular oxygen as the oxidant and operating under very mild conditions represents a new direction. ,− O 2 exists in the triplet state in its ground state and by photocatalysis can be turned into reactive oxygen species (ROS) including superoxide (O 2 •– and HO 2 • ), hydroxyl radicals ( • OH), and singlet oxygen ( 1 O 2 ). Among them, 1 O 2 is a mild yet efficient oxidant and has served as a robust ROS with multiple applications ranging from organic synthesis to photodynamic cancer therapy. , Hence, it is reasonable to envisage that the engagement of 1 O 2 in photocatalysis may benefit the selectivity control in green oxidation reactions, especially those involving C–C formation under O 2 atmosphere like the arylethylenes to 4-aryltetralone transformation, although this remains unexplored thus far.…”