Ralf Karch

Ruthenium-Catalyzed Stereoselective anti-Markovnikov-Addition of Thioamides to Alkynes

A catalyst system generated in situ from bis(2-methallyl)-cycloocta-1,5-diene-ruthenium(II) and a phosphine was found to efficiently catalyze the addition of thioamides to terminal alkynes with exclusive formation of the anti-Markovnikov thioenamide products. The stereoselectivity of the addition is usually high and controlled by the choice of the phosphine ligand, whereas the (E)-isomers are predominantly formed in the presence of tri(n-octyl)phosphine, the use of bis(dicyclohexylphosphino)methane preferentially leads to the formation of the (Z)-configured thioenamides.

(R p)-1-{(R)-(Dimethyl­amino)[2-(diphenyl­phosphan­yl)phen­yl]methyl}-2-(diphenyl­phosphan­yl)ferrocene chloro­form solvate

The absolute configuration of the title molecule, [Fe(C5H5)(C38H34NP2)]·CHCl3, is R,R p. The molecular structure is similar to the structure of the solvent-free compound [Fukuzawa, Yamamoto & Kikuchi (2007 ▶). J. Org. Chem. 72, 1514–1517], but some torsion angles about the P—Cphenyl bonds differ by up to 25°. The P atoms and the N atom have a distorted trigonal-pyramidal geometry. The chloroform solvate group donates a C—H⋯π bond to the central benzene ring and is also involved in six intermolecular C—H⋯Cl contacts with H⋯Cl distances between 2.96 and 3.13 Å.