Ethanes aryl-substituted—

The use of phosphide nucleophiles in an SN2 attack on alkyl-substituted cyclic sulfates allows access to a wide range of phospholane derivatives. However, if aryl-substituted cyclic sulfates are used, elimination and racemization processes compete with substitution. To access bis(2,5-diphe-nylphospholano)ethane (4), an alternative strategy was required (Scheme 13.2).14... 

Patent Tri-Aryl-Substituted-Ethane PDE4 Inhibitors... 

Nickel(O) triphenylphosphine can be used to couple aryl halides and alkenes to synthesize substituted olefins [149], 1,2-bis[(di-2-propylphosphino)benzene]nick-el(0) can be used to couple aryl halides [150], and l,2-bis[(diphenylphos-phino)ethane]nickel(0) can be used to prepare benzoic acid from bromobenzene in the presence of carbon dioxide [151]. 

Iron complexes containing bidentate alkyl and aryl phosphorus ligands cleave a variety of C-H bonds under mild conditions, Hydrido acetylide complexes were prepared by oxidative addition of primary acetylenes in the Fe(DPPE)2 and the Fe(DMPE)2 systems [DPPE = bis(diphenylphos-phino)ethane, DMPE = bis(dimethylphosphino)ethane]. The Fe(DMPE)2 system also cleaves C-H bonds of activated methyl groups, aromatic compounds, and certain other sp hybridized molecules. The C-H cleavage reactions are reversible, resulting in equilibrium mixtures of isomeric products in many cases. Studies of substituted benzenes show that while product stability is favored by electron withdrawing substituents, steric effects play a predominant role in the determination of product distribution. 

A commercial synthesis of 2-bromothiophene was reported in the year 2014 (14PAT-2).The synthesis consists of oxidative bromination of thiophene with hydrogen bromide and hydrogen peroxide in dichloro-ethane at 40 °C. The method is amenable for large-scale production. Additionally, sequential one-pot syntheses of tri- and tetra-substituted thiophene and fluorescent push-pull thiophene acrylates involving (het)aryl dithioesters as thiocarbonyl precursors were reported (14MI-001). 

Even better results were achieved using the tridentate oxygen ligand - 1,1,1-tris (hydroxymethyl)ethane (Scheme 3.32). Nearly quantitative yields were found in the reaction involving various aryl iodides (including o-MeO-substituted) with aryl thiols and alkyl thiols [63]. 

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