Thiocyanates thiolates

Replacement of iodine in (perfluoroalkyl)ethyl iodides predominates over the usual conversion to olefins when the reagent is very nucleophilic and weakly basic Soft nucleophiles like sodium thiocyanate and sodium thiolates react well in displacements [46, 47] (equation 42)... 

Some interesting cases of isomerism in bridged complexes do arise. The thiocyanate bridged complex shown in Figure 3.41 is a good example of the ambidentate behaviour of the thiocyanate (confirmed by X-ray) while in the complexes [Pt(PR3)(SR)(SR )]2 the choice of isomer is determined by the order in which the thiolate groups are introduced (Figure 3.42). 

Thiolates, generated in situ by the action of ammonium tetra-thiomolybdate on alkyl halides, thiocyanates, and disulfides, undergo conjugate addition to a, (1-unsaturatcd esters, nitriles, and ketones in water under neutral conditions (Eq. 10. II).29 Conjugate addition of thiols was also carried out in a hydrophobic ionic liquid [bmim]PF6/water-solvent system (2 1) in the absence of any acid catalyst to afford the corresponding Michael adducts in high to quantitative yields with excellent 1,4-selectivity under mild and neutral conditions (Eq. 10.12). The use of ionic liquids helps to avoid the use of either acid or base catalysts... 

For the quantitative synthesis of thiocyanates by reaction with cyanogen chloride or cyanogen bromide it is essential to start with thiolates instead of thiols. The product salts are then removed by washing of the products with water. Thus, the various heterocyclic thiocyanates 224a-d are easily obtained in pure form by either gas-solid (CICN) or solid-solid (BrCN) reaction [92] (Scheme 29). 

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