Thiocarbene complex

Alkylation of thioacyl ligands provides a route to thiocarbene complexes. Faraone and co-workers have prepared iridium thiocarbene complexes 20 and 21 by methyl iodide addition to Ir(I) thiocarbonyl... 

In Figure 2.2 the most important synthetic approaches to alkoxy- or (acy-loxy)carbene complexes from non-carbene precursors are sketched. Some of these strategies can also be used to prepare amino- and thiocarbene complexes. These procedures will be discussed in detail in the following sections. In addition to the methods sketched in Figure 2.2, many complexes of this type have been prepared by chemical transformation of other heteroatom-substituted carbene complexes. Because of the high stability of most of these compounds, many different reactions can be used to modify the substituents at C without degrading the carbon-metal double bond. The generation of heteroatom-substituted carbene complexes from other carbene complexes will be discussed in Section 2.2. 

The thiocarbene complex [(CO)5WC(SMe)Me] has been prepared by the reaction of [(CO)sWC(OMe)Me] with HSMe at room temperature. The position of the v(C )) stretching frequencies, the energy barrier for rotation about the C—S bond, the ionization potential, and the dipole moment of the... 

The second example shows that such a reaction need not always lead to an uncharged system. If, instead of thiocarbene complexes, amino-carbene complexes are treated with hydrogen halides, products of saltlike character are isolable (66). One finds the halogen at the metal and the hydrogen at the removed carbene ligand, and one obtains iminium halo-genopentacarbonylmetalates ... 

Even Lewis acid adducts of the acyl metalate 11 (Section 8.3.1.1, Scheme 8) proved effective in generating benzannulation products. The reaction of a trimethylsilyloxy chromium carbene complex with 3-hexyne to give the respective semi-silylated hydroquinone tricarbo-nylchromium complex in 35 % yield [30a] and the use of titanoxycarbene complexes [30b] constitute such examples. Thiocarbene complexes form hydrothioquinones in a Lewis acid supported benzannulation reaction [32]. 

Thiazadiphosphole, synthesis with phosphaalkenes, 18-19 Thiocarbene complexes, synthesis, 224-225... 

A number of reactions of organothiols with complexes of alkoxycar-benes, isocyanides, or thiocarbonyls, leading to thiocarbene complexes, have been reviewed (4,125,126). Further related examples include the conversion of a chlorocarbene to a dithiocarbene by reaction of the ruthenium complex 154 with RSH (R = Me, p-tolyl) or HSCH2CH2SH to give the dithiocarbene compounds 155 and 156 (82). 

The reaction between the thiocarbene complex 413 and (Cp3)2C=NC(0)R (R = Ph, P-FQH4) leads to scission of the carbene ligand and transfer of the nucleophilic SMe fragment to the electrophilic center of the acylamine. Protonation, effected either by the rest of the carbene or the solvent, results in a thioether derivative (414) (249). 

Complexes of type 458 can be obtained by the addition of nucleophiles, R [M] (MeLi, MeMgBr, CsHuMgBr, PhMgBr, Me2CuLi, Bu2CuLi, Me2CuLi) to cationic thiocarbene complexes of type 457 (R = H or Me, R = Me or Ph) (277). 

Photolytic reactions of the thiocarbene complexes are conducted in a reation vessel surrounded by a filter solution for X > 400 nm. This solution is prepared by the addition of 54 mL of 30% aqueous ammonia to a solution of 4.5 g of copper sulfate in 6 mL of water. The solution is added to a second solution containing 22.5 g of sodium nitrite and 30 mL of water. Finally, the mixture is diluted with water to 1000 mL. 

Angelici has demonstrated that protonation of the methylthiocarbyne complex HBpz3(CO)2W =CSMe affords the cationic Fischer-type rj -thiocarbene complex [HBpz3(C0)2W-Ti -(=C(H)SMe)][CF3S03] [421. However, the comparable cyclopentadienyl substituted rj -thiocarbene complexes [Cp(CO)2M-r 2-(=C(R)SMe)][BF4] still contain a nucleophilic carbene carbon whereas an amphiphilic behavior is found for the trimethylphosphine-sub-stituted derivatives Thus, nucleophiles as well as electrophiles add to the carbene carbon of [Cp(CO)(PMe3)M-Ti2-(=C(R)SMe)][BF4] [41]. 

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