Search results
Results from the WOW.Com Content Network
Wilkinson's catalyst (chloridotris(triphenylphosphine)rhodium(I)) is a coordination complex of rhodium with the formula [RhCl(PPh 3) 3], where 'Ph' denotes a phenyl group. It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in tetrahydrofuran or chlorinated solvents such as dichloromethane .
The difference in regioselectivity is more pronounced in the hydroboration of vinylarenes with HBcat. Wilkinson's catalyst or the cation Rh(COD) 2 (in the presence of PPh 3) produces the Markovnikov product. [12] [13] The anti-Markovnikov product is produced in the absence of a catalyst. [14]
The Tsuji–Wilkinson decarbonylation reaction is a method for the decarbonylation of aldehydes and some acyl chlorides. The reaction name recognizes JirÅ Tsuji, whose team first reported the use of Wilkinson's catalyst (RhCl(PPh 3) 3) for these reactions: RC(O)X + RhCl(PPh 3) 3 → RX + RhCl(CO)(PPh 3) 2 + PPh 3
The reaction required tin tetrachloride and a stoichiometric amount of Wilkinson's catalyst: An equal amount of a cyclopropane was formed as the result of decarbonylation. The first catalytic application involved cyclization of 4-pentenal to cyclopentanone using (again) Wilkinson's catalyst. [4] In this reaction the solvent was saturated with ...
Dehydrogenative coupling of primary silanes using Wilkinson's catalyst is slow and dependent on the removal of H 2 product. This conversion proceeds by oxidative addition of the Si-H bond and elimination of dihydrogen. [7] Tris(pentafluorophenyl)borane (B(C 6 F 5) 3)) is yet another catalyst for the dehydrogenative coupling of tertiary silanes ...
An example of this is the Tsuji–Wilkinson decarbonylation reaction using Wilkinson's catalyst. (Strictly speaking, the noncatalytic version of this reaction results in the formation of a rhodium carbonyl complex rather than free carbon monoxide.)
Knowles developed one of the first asymmetric hydrogenation catalysts by replacing the achiral triphenylphosphine ligands in Wilkinson's catalyst with chiral phosphine ligands. This experimental catalyst was effective for enantioselective synthesis , achieving a modest 15% enantiomeric excess .
An alkyne trimerisation is a [2+2+2] cycloaddition reaction in which three alkyne units (C≡C) react to form a benzene ring. The reaction requires a metal catalyst. The process is of historic interest as well as being applicable to organic synthesis. [1] Being a cycloaddition reaction, it has high atom economy.