Carbon-sulfur bond formation alkynes

Carbon-Sulfur Bond Formation. The oxidation of sulfl-nates by CAN provides an easy entry to sulfonyl radicals, which can be trapped by various alkenes, especially electron-rich ones, to afford sulfones. For example, the reaction of sodium 2-naphtha-lenesulflnate with 1-vinylcyclobutanol in the presence of CAN furnishes the ring-enlarged product (eq 27). With the aid of sodium iodide, the CAN-mediated oxidative addition of sulflnates to styrene affords vinyl sulfones and the addition to alkynes leads to /3-iodo vinyl sulfones. ... 

The molecular building-block technique, which involves a wide range of organic reacfions. For example, nucleophilic substifufions, in particular, those involving sulfur, Schiff-base condensations, Mitsonubu reactions, carbon-carbon bond formation e.g. the Suzuki reaction), amide-bond formation, alkyne - coupling reactions, etc. 

Ananikov VP, Zalesskiy SS, Orlev NV, Beletskaya IP (2006) Nickel-catalyzed addition of benzenethiol to alkynes formation of carbon-sulfur and carbon-carbon bonds. Russ Chem Bull Int Ed 55 2109-2133... 

Fluorine migration from the CF3 group to the metal occurs with Cr", Fe ", Co ", Pt" and Zn" but not with Ru ", Rh" , Ni" and Pd". The reaction pathway for the zinc complexes is shown in Scheme 3. The molecular ion (48) loses a CFj radical from one monothio-)8-diketone moiety to give the ion (49), which then loses carbon monoxide to yield the fragment (50). Sulfur is ejected from (50) with the concomitant formation of a zinc-carbon bond in the species (51), which can subsequently lose the alkyne RC=CH to give the mono-ligand ion [ZnL] (52). The second ligand moiety loses Cp2 with the formation of a zinc-fluorine bond in the ion (53). 

The free radical addition of a thiol to carbon-carbon double or triple bonds is a well-established reaction. It represents one of the most useful methods of synthesizing sulfides under mild conditions. Since its discovery [5] and its much later formulation as a free-radical chain reaction (Scheme 1) [6], the anti-Markovnikov addition of thiols to unsaturated compounds has been the subject of many reviews [8, 9]. These reactions were originally initiated by thermal decomposition of peroxides or azocompounds, by UV irradiation or by radiolysis [10]. (An example of addition of 1-thiosugar to alkenes initiated by 2,2 -azobisisobutyronitrile (AIBN) [11] is reported in equation (1)). More recently, organoboranes have been used as initiators and two examples (Et3B and 9-bora-bicyclo [3.3.1.] nonane) are reported in equations (2) and (3) [12,13]. Troyansky and co-workers [14a] achieved the synthesis of macrocycles like 12- and 13-membered sulfur-containing lactones by the double addition of thiyl radical to alkynes. An example is depicted in equation (4). The same approach has also been applied to the construction of 9- and 18-membered crown thioethers [14b]. The radical chain addition of thiyl radicals to differently substituted allenes has been considered in detail by Paste and co-workers [15], who found that preferential attack occurs at the central allenic carbon and gives rise to a resonance-stabilized ally radical. The addition of benzenethiol to allenic esters has been reported and the product formation has been similarly inferred (equation (5)) [16]. 

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