title: Pd(II)-catalyzed ligand controlled synthesis of pyrazole-4-carboxylates and benzo[b]thiophene-3-carboxylates.
abstract: Cyclization-carbonylation of α,β-alkynic hydrazones and (o-alkynylphenyl) (methoxymethyl) sulfides with Pd(tfa)2 in DMSO/MeOH afforded methyl pyrazole-4-carboxylates and benzo[b]thiophene-3-carboxylates, respectively, in good yields. A simple change of the ligand (solvent) allowed controlled, effective switching between cyclization-carbonylation-cyclization-coupling (CCC-coupling) reactions and cyclization-carbonylation reactions.
authors.affiliation: Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan. kkk@phar.toho-u.ac.jp.
authors.forename: Yogesh Daulat
authors.initials: YD
authors.lastname: Dhage
authors.forename: Hiroki
authors.initials: H
authors.lastname: Daimon
authors.forename: Cheng
authors.initials: C
authors.lastname: Peng
authors.forename: Taichi
authors.initials: T
authors.lastname: Kusakabe
authors.forename: Keisuke
authors.initials: K
authors.lastname: Takahashi
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kanno
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Inouye
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kato
mesh_terms: D002264:Carboxylic Acids / Q000138:chemical synthesis*; D002384:Catalysis; D002413:Cations, Divalent; D003500:Cyclization; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D006835:Hydrazones / Q000737:chemistry*; D008024:Ligands; D000432:Methanol / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis*; D013876:Thiophenes / Q000138:chemical synthesis*
chemical_list: D002264:Carboxylic Acids; D002413:Cations, Divalent; D006835:Hydrazones; D008024:Ligands; D011720:Pyrazoles; D013876:Thiophenes; D010165:Palladium; D000432:Methanol; D004121:Dimethyl Sulfoxide