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Trapping Reactions of an Intermediate Containing a Tungsten-Phosphorus Triple Bond with Alkynes

Schiffer, Michael and Scheer, Manfred (2001) Trapping Reactions of an Intermediate Containing a Tungsten-Phosphorus Triple Bond with Alkynes. Chemistry - A European Journal 7 (9), pp. 1855-1861.

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Abstract

The thermolysis of the phosphinidene complex [Cp*P ${W(CO)5}$ 2] (1) in toluene in the presence of tBuCCMe leads to the four-membered ring complexes [[ ${2-C(Me)C(tBu)}$ Cp*(CO)W(3-P) ${W(CO)3}$ ] ${4:1:1-P{W(CO)5}WCp*(CO)C(Me)C(tBu)}$ ] (4) as the major product and [[W ${Cp*(CO)2}$ W(CO)2WCp*(CO) ${1:1-C(Me)C(tBu)}$ ](,3:2:1-P2 ${W(CO)5}$ ] (5). The reaction of 1 with PhCCPh leads to [[W(CO)2 ${2-C(Ph)C(Ph)}$ ][(4:1-P ${W(CO)5}$ W ${Cp*(CO)2}$ C(Ph)C(Ph)]] (6). The products 4 and 6 can be regarded as the formal cycloaddition products of the phosphido complex intermediate [Cp*(CO)2WPW(CO)5] (B), formed by Cp* migration within the phosphinidene complex 1. Furthermore, the reaction of 1 with PhCCPh gives the minor product [[ ${2:1-C(Ph)C(Ph)}$ 2 ${W(CO)4}$ 2]{,1:1-P{C(Me){C(Me)}3C(Me)}{C(Ph)}{C(Ph)}] (7) as a result of a 1,3-dipolaric cycloaddition of the alkyne into a phosphaallylic subunit of the Cp*P moiety of 1. Compounds 4-7 have been characterized by means of their spectroscopic data as well as by single-crystal X-ray structure analysis. [brace not closed]