142523-69-1Relevant articles and documents
First intramolecular Diels-Alder reactions using chromone derivatives: Synthesis of chromeno[3,4-: B] xanthones and 2-(benzo [c] chromenyl)chromones
Albuquerque, Hélio M. T.,Santos, Clementina M. M.,Cavaleiro, José A. S.,Silva, Artur M. S.
, p. 4251 - 4260 (2018)
A series of novel (E)-2-(2-propargyloxystyryl)chromones and (E,E)-2-[4-(2-propargyloxyphenyl)buta-1,3-dien-1-yl]chromones were designed and synthesized via aldol condensation of 2-methylchromones with 2-propargyloxy(benzaldehyde and cinnamaldehyde), respectively. Both chromone derivatives were used as substrates in microwave-assisted intramolecular Diels-Alder reactions, affording chromeno[3,4-b]xanthones and 2-(benzo[c]chromenyl)chromones. This is the first report involving chromone derivatives in intramolecular Diels-Alder reactions for the synthesis of new oxygen heterocycles, namely xanthone- and flavone-type compounds.
Visible light mediated synthesis of 6H-benzo[c]chromenes: transition-metal-free intramolecular direct C-H arylation
Budén, María E.,Heredia, Micaela D.,Puiatti, Marcelo,Rossi, Roberto A.
supporting information, p. 228 - 239 (2021/12/29)
A synthetic approach towards the 6H-benzo[c]chromene ring under visible light and transition-metal-free conditions has been developed. Benzochromenes are synthesized from the corresponding (2-halobenzyl) phenyl ethers or (2-halophenyl) benzyl ethers using
Pd-Catalyzed ipso, meta-Dimethylation of ortho-Substituted Iodoarenes via a Base-Controlled C-H Activation Cascade with Dimethyl Carbonate as the Methyl Source
Wu, Zhuo,Wei, Feng,Wan, Bin,Zhang, Yanghui
supporting information, p. 4524 - 4530 (2021/05/04)
A methyl group can have a profound impact on the pharmacological properties of organic molecules. Hence, developing methylation methods and methylating reagents is essential in medicinal chemistry. We report a palladium-catalyzed dimethylation reaction of ortho-substituted iodoarenes using dimethyl carbonate as a methyl source. In the presence of K2CO3 as a base, iodoarenes are dimethylated at the ipso- and meta-positions of the iodo group, which represents a novel strategy for meta-C-H methylation. With KOAc as the base, subsequent oxidative C(sp3)-H/C(sp3)-H coupling occurs; in this case, the overall transformation achieves triple C-H activation to form three new C-C bonds. These reactions allow expedient access to 2,6-dimethylated phenols, 2,3-dihydrobenzofurans, and indanes, which are ubiquitous structural motifs and essential synthetic intermediates of biologically and pharmacologically active compounds.
Choline Hydroxide as a Versatile Medium for Catalyst-Free O-Functionalization of Phenols
Joo, Seong-Ryu,Kim, Seung-Hoi,Kwon, Gyu-Tae,Park, Soo-Youl
, p. 1200 - 1205 (2020/11/30)
A versatile synthetic protocol for benzyl phenyl ether preparation via O-alkylation of phenolic oxygen with readily available benzyl derivatives was demonstrated. The newly designed procedure was carried out using an eco-friendly medium, room-temperature ionic liquid (choline hydroxide), under metal- and base-catalyst-free aerobic conditions. The reaction platform was also successfully applied to phenol protection strategy.