Oxidative 1,2-Difunctionalization of Ethylene via Gold-Catalyzed Oxyarylation

Oxidative 1,2-Difunctionalization of Ethylene via Gold-Catalyzed Oxyarylation
Matthew J. Harper†, Edward J. Emmett, John F. Bower , and Christopher A. Russell

School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, United Kingdom

Link:J. Am. Chem. Soc., 2017, 139 (36), pp 12386–12389

DOI: 10.1021/jacs.7b06668
Publication Date (Web): August 22, 2017



Abstract



Under the conditions of oxidative gold catalysis, exposure of ethylene to aryl silanes and alcohols generates products of 1,2-oxyarylation. This provides a rare example of a process that allows catalytic differential 1,2-difunctionalization of this feedstock chemical.

Pd(II) Complexes Ligated by 1,3-Bis(diphenylphosphino)calix[4]arene: Preparation, X-ray Structures, and Catalyses

Pd(II) Complexes Ligated by 1,3-Bis(diphenylphosphino)calix[4]arene: Preparation, X-ray Structures, and Catalyses

Kengo Hirasawa, Shinya Tanaka*, Takeru Horiuchi, Takahiro Kobayashi, Takumi Sato, Naoya Morohashi, and Tetsutaro Hattori*
Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, 6-6-11 Aramaki-Aoba, Aoba-ku, Sendai 980-8579, Japan
Organometallics, Article ASAP
DOI: 10.1021/acs.organomet.5b00999
Publication Date (Web): January 22, 2016

syn-1,3-Bis(diphenylphosphino)-2,4-dimethoxycalix[4]arene (7) was synthesized via an Ullmann-type phosphinoylation of the syn-1,3-bis(triflate ester) (2) of p-tert-butylcalix[4]arene, followed by reduction of the phosphinoyl moieties and subsequent methylation of the remaining hydroxy groups. The treatment of diphosphine 7 with 2 molar equiv of PdCl2(MeCN)2 in benzonitrile afforded di-μ-chloro-bridged dinuclear palladium complex 8, formulated as Pd2(7)Cl4, whereas the same reaction conducted in acetonitrile with 1 molar equiv of PdCl2(MeCN)2 yielded mononuclear palladium complex 9, formulated as [Pd(7)Cl(MeCN)]Cl. Complex 9 was transformed into dicationic complex 11, formulated as [Pd(7) MeCN)2](BF4)2, by treatment with AgBF4 in dichloromethane, followed by the addition of acetonitrile. On the other hand, refluxing complex 9 in 1,2-dichloroethane yielded neutral complex 12, formulated as Pd(7)Cl2. In each of the mononuclear complexes, the palladium ion adopts a tetracoordinated square-planar geometry perpendicular to the mean plane defined by the macrocycle, and two phosphorus atoms occupy trans coordination sites. Consequently, an acetonitrile or chlorine ligand coordinates through the cavity of the calixarene, while another acetonitrile or chlorine ligand occupies the exo position. Dicationic complex 11 promoted Suzuki–Miyaura coupling between aryl chlorides and phenylboronic acid and the ring-opening reaction of an epoxide with thiophenol.