REACTION OF UNSYMMETRICAL THIOALKYNES R-C-EQUIVALENT-TO-C-SC2H5, R = CH3, C6H5, WITH IRON AND RUTHENIUM CARBONYLS - HOW TO BUILD A POLYNUCLEAR COMPOUND USING THE C-S CLEAVAGE

A thorough investigation of reactions of amino and phosphinoalkynes wi th metal carbonyls showed the significant influence of the nature of t he heteroatom on the reaction. This paper deals with the reactions of two unsymmetrical thioalkynes RC=CSC2H5, R=CH3 or C6H5, with iron and ruthenium carbonyls. About twenty characterized compounds helped to de scribe the sulfur influence on the behaviour of those two thioalkynes. (1) Two thioalkynes couple via the triple bond according to a classic al reaction type. However, the alkyne asymmetry yields three types of coupling which were all observed. (2) The particular role of sulfur is displayed first by the cleavage of one or the other carbon-sulfur bon d, or more seldomly both of them simultaneously, and second by the wel l known ability of sulfur to ligate metal. (3) The combination of thes e features led us to modulate the increase of nuclearity from two to f ive iron atoms.