Reactions with sulfur nucleophiles

Thiophene sulfonation can be achieved by electrophilic substitution (see Sect. 2.6). Nucleophilic sulfonylation of thiophene, with displacement of a leaving group, is 

---

Reaction with Sulfur Nucleophiles, Because sulfai is highly nucleophilic, reactions of aziridines with sulfur nucleophiles generally proceed rapidly (111) and with good yields. The reaction of hydrogen sulfide [7783-06S-J with ethyleneimine yields cysteamine [60-23-1] (2-mercaptoethylamine) or bis(2-aminoethyl)sulfide [871-76-1] (2,112) depending on the molar ratio of the reactants. The use of NaHS for the synthesis of cysteamine has also been described (113). 

Table X lists a few of the haloaliphatic substrates which were found to satisfy Expression 7 for some of the sulfur nucleophiles encountered (or closely related to those found) in natural waters. The results in the table indicate that among the substrates listed in Tables IV through IX, it is principally the brominated compounds for which the reactions with sulfur nucleophiles are likely to compete effectively with hydrolysis. However, due to the long residence times of groundwaters in hydrogeologic systems, reactions which are not as rapid as hydrolysis may also be significant.

The usual azine reactions with sulfur nucleophiles are observed, e.g. chlorine substitution in the pyridazine (676). Oxo groups in activated positions are thiated using phosphorus... 

Other neutral cyclopentadienyl alkyne complexes have been prepared by chloride substitution reactions with sulfur nucleophiles pentafluoro-phenylthiolate products have been reported [Eq. (35)] (95). These reactions are sensitive to the identity of the sulfur nucleophile (96), and attack at an alkyne carbon to yield 772-vinyl ligands is common (97). 

Reactions with Sulfur Nucleophiles. The use of sulfur nucleophiles in palladium-catalyzed allylic substitution reactions is less well documented than that of carbon, nitrogen and oxygen nucleophiles. The asymmetric synthesis of allylic sulfones utilizing a catalytic phase transfer system has been used to produce (35)-(phenylsulfonyl)cyclohex-l-ene on a 45 g scale (eq 10). In many cases, it has been reported that allylic carbonates are more reactive than allylic acetates in asymmetric allylic substitution... 

Reaction with sulfur nucleophiles has also been investigated. For example, dioxene-dioxetane (Eq. 76) gave on reaction with diphenylsulfide, the dioxene-epoxide and the acetal of benzil. On the other hand, the reaction of dimethyl-1,2-dioxetane with dimethyl sulfoxylate gave the sulfurane (Eq. 77). ... 

In addition to accelerating degradation rates for halogenated aliphatics, reaction with sulfur nucleophiles will have significant consequences with respect to reaction product distributions. Schwarzenbach et al. (1985) have observed the formation of thiols and dialkyl sulfides from the Sn2 reactions of primary alkyl bromides with HS (Figure 2.12). 

---