Thiophenols desulfurization

Removal of sulfur from these complexes remains challenging. Catalysts such as [M(COD)(PPh3)2]+ (M = Rh, Ir) only hydrogenate the C=C bond of benzothio-phene, whereas the hydrogenation with rhodium triphos complexes gives 2-ethyl-thiophenol.148 The addition of Co4(CO)i2 to (21-XXVIII, ML, = Cp Ir), however, leads to partial desulfurization, presumably with formation of cobalt sulfide.149... 

Thiophenol adds to acrylates in the presence of alkaloids to yield esters with ee s of up to 51 % 169. These products can be easily desulfurized by Raney nickel. 

Position 4 in androstanes will undergo some reactions that are more typically associated with the chemistry of aromatic compounds. Treatment of methyltestosterone (14-1) with formaldehyde and thiophenol thus leads to the formation of the thiomethylated derivative 19-1 (Scheme 5.19). Raney nickel then desulfurizes the product, expelling the benzene ring in the process to afford 4,17-dimethyltestosterone (19-2). 

The sulfur-abstracting capacity of [(Cp )2Mo2Co2(CO)4( 3-S)2(/i4-S)] (64) vis-a-vis sulfur-containing molecules other than thiophene has been studied. For example, whereas sulfur abstraction from thiophene produces a mixture of hydrocarbons cracked to various extents (but notably no butadiene, which is a product of HDS of thiophene over heterogeneous catalysts), a completely clean reaction is seen for thiols (RSH) which are desulfurized to Thiophenol (PhSH) is desulfurized... 

Treatment of hexopyranosid-2-ulose derivatives with DAST pioduced the gem-difluorides only if both neighbouring groups were either axial or equatorial. The stereoselective aldol coupling of 2-deoxy-hexopyranosid-3-uloses with various carbohydrate aldehydes is covered in Chapter 14. The chemoselective reduction of enones in the presence of allyl ethers by the conjugate addition of thiophenol followed by radical desulfurization with BujSnH has been achieved. ... 

Early in the 1990s, Kumar and co-workers described an asymmetric synthesis of (5)-naproxen by means of a thia-Michael addition of thiophenol to acrylate 115 (Scheme 31.39). Desulfurization followed by acid cleavage... 

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