Thiolation palladium-catalyzed

In 1979, the reaction of styrenyl and hexenyl halides with an alkali metal thiophenolate and ethanethiolate was reported (Equation (40))130 Reaction yields exceeded 90%, and the products retained the geometry of the starting olefin. In contrast to the stereospecificity of palladium-catalyzed couplings involving vinyl halides, nickel-catalyzed couplings of vinyl halides with thiolates gave mixtures of stereoisomeric products 131... 

The palladium-catalyzed C-Se bond formation79-81 and the platinum-catalyzed carboselenation of alkynes with selenoesters have been reported in analogy with the thiolate chemistry. An electron-withdrawing or electron-donating group on the aromatic residue leads to the formation of the desired carboselenation product with acceptable yields. Functionalities like benzyl, hydroxyl, or nitrile group are tolerant with the reaction conditions. This method provides a new access to the functionalized vinylselenide 60,82 molecules of interest as key intermediate (Scheme 19) 85... 

C.i. Palladium-Catalyzed Cross-Coupling of Thiolates with Aryl and Vinyl Halides... 

Platinum(O) complexes such as Pt(PPh3)4 also catalyze carbonylative thiolation of allenes, affording a,p- and p,y-unsaturated thioesters in good yields [116]. When 2-iodobenzenethiols are employed for the palladium-catalyzed carbonylation with... 

In 1996, Ogawa et al. reported the hydrothiolahon of an allene catalyzed by Pd(OAc)2 to provide 32, whose formahon can be explained as follows (1) insertion of the allene into the Pd-S bond of Pd(SPh)2 to give a tt-allyl palladium thiolate 33, and (2) protolysis by PhSH to form 32 and Pd(SPh)2 (Eq. 7.24) [35], The authors proposed the direct reachon of a o-aHyl palladium with PhSH before the formation of 33. 

Several Pd11 complexes with thiolate or thioether derivative ligands have been studied to be applied in the hydroxycarbonylation reaction.394 Aminothiolate complexes of palladium with PPh3 catalyze the conversion of styrene to 2-phenylpropionic acid in high yield and excellent regioselectivity.644 Under mild conditions and in the presence of a catalytic amount of an S, TV-chelated palladium or//zo-amino-arenethiolate complex, styrene reacts with CO and oxalic acid or water to selectively give 2-phenylpropanic aid in high yield.645... 

Pyrimidine thioethers may also be synthesized via direct Pd-catalyzed C—S bond formation between halopyrimidines and thiolate anions. For very unreactive thiol nucleophiles such as 2-thiopyrimidine, both a strong base and a palladium catalyst are essential. Without a palladium catalyst or replacing f-BuONa with K2C03, the reaction failed to furnish the desired pyrimidine thioether [49]. 

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