Formation of carbon-sulfur bonds

C. Formation of Carbon-Sulfur Bonds Depending on the conditions, ethvlenimine reacts with hydrogen sulfide to give either /3-arainoethy] mercaptan or ftjS -diaminodiethyl galfide .3 (Kq, 66). Other examples of the reaction of organic... 

In contrast to isocyanates, isothiocyanates have hardly been examined as cycloaddition components, because the strong coordination of organosulfur compounds frequently deactivates a catalytic species [21]. Some organoruthe-nium complexes, however, recently proved to be efficient catalysts for the formation of carbon-sulfur bonds [21]. The catalytic cycloaddition of diynes with isothiocyanates was also successfully achieved using Cp RuCl(cod) as a precatalyst [22]. Importantly, the cycloaddition took place at the C=S double bonds of the isothiocyanates to afford thiopyranimines 26 (Eq. 13). This reaction requires 10 mol % of the precatalyst as well as the diynes possessing a quarternary carbon center at the 4-position. When excess amounts of carbon disulfide were also employed in place of the isothiocyanates, a bicyclic dithiopyrone 26 [X is C(C02Me)2, Z is S] was obtained in 50% yield. 

Cyclizations by formation of carbon-sulfur-bonds belong to the best studied reactions which use the dilution principle. Usually bromides react with thiols [7 b, 17, 18], thiuronium salts [19], or with sodium sulfide [20] and thioacetamide, respectively. The formation of C—S bonds represents one of the most valuable methods to synthesire medium-membered cyclophanes such as 4-8 [7 b, 18 b, 20d, 21]. 

FORMATION OF CARBON-SULFUR BONDS FROM ADDITIONS TO -ir-BONDS Formation cfThiiranes... 

Addition Reactions with Formation of Carbon-Sulfur Bonds... 

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