Coupling of Internal Alkynes in TpMe2Ir Derivatives: Selective Oxidation of a Noncoordinated Double Bond of the Resulting Iridacycloheptatrienes
摘要:
The reaction of different Tp(Me2)Ir derivatives and dimethylacetylene dicarboxylate (DMAD) allows the preparation of three different metallacycloheptatriene complexes and an unusual allyl-terminated metallacycle. The C atoms of distant C=C bonds in the metallacycles, including aromatic ones, can be converted selectively to the corresponding keto functionality under mild conditions.
O-Dihaloarenes as aryne precursors for nickel-catalyzed [2 + 2 + 2] cycloaddition with alkynes and nitriles
作者:Jen-Chieh Hsieh、Chien-Hong Cheng
DOI:10.1039/b801870g
日期:——
o-Dihaloarenes acting as aryne precursors react with acetylenes and nitriles catalyzed by the NiBr(2)(dppe)/dppe/Zn system to give substituted naphthalene, phenanthridine or triphenylene derivatives depending on the reaction conditions in moderate to excellent yields with good tolerance of functional groups.
Reaction cascades initiated by nucleophilic attack of heteropentalene mesomeric betaine and nitrogen-rich mesoionic tetrazolium-5-amides on electron-deficient unsaturated compounds. Synthesis of novel heterocyclic systemsElectronic supplementary information (ESI) available: synthesis of 4b; reactions of 11 and 17 with electron-deficient unsaturated compounds; alternative synthesis of 19 from 20. See http://www.rsc.org/suppdata/ob/b2/b211000h/
The reactions of heteropentalene mesomeric betaine 1 and nitrogen-rich mesoionic tetrazolium-5-amides 4, 11 and 16-18 with electron-deficient unsaturated compounds have been studied. Novel heterocyclicsystems, tetrazolo[4,5-a][1,7]benzodiazonine inner salt 2 and 3-oxo-3,7-dihydro-2H-pyrazolo[3,4-b]pyridine 5, have been synthesized by the reactions of dimethyl acetylenedicarboxylate with 1 and tetrazolium-5-anilide
Benzene rings of N-alkyltoluidine and benzene (or iodobenzene) in acetic acid were annelated with acetylenedicarboxylates by palladium(II) acetate to give N-alkylindole-2,3-dicarboxylate and naphthalene-1,2,3,4-tetracarboxylate. The formation of the products are explained in terms of toluidine radical cation intermediates.
Selective Palladium-Catalyzed Cocyclotrimerization of Arynes with Dimethyl Acetylenedicarboxylate: A Versatile Method for the Synthesis of Polycyclic Aromatic Hydrocarbons
derivatives 4,5-difluorobenzyne (1b) and 3-methoxybenzyne (2) undergo chemoselective palladium-catalyzed [2 + 2 + 2]-cocyclotrimerization with dimethyl acetylenedicarboxylate (DMAD) to afford the corresponding phenanthrenes and/or naphthalenes. The major products are phenanthrenes if Pd(PPh(3))(4) is used as the catalyst, naphthalenes if Pd(2)(dba)(3) is used. When the method is applied to polycyclic arynes
acetylenedicarboxylate esters and diphenylacetylene efficiently proceeds in the presence of a palladium catalyst with use of silver carbonate as base to produce the corresponding tetrasubstituted naphthalenes.