543707-50-2Relevant articles and documents
Metallacyclopentatriene-butadienyl carbene rearrangement in the oxidative coupling of alkynes mediated by [RuCp(SbR3)(CH3CN)2]+ (R = Ph, n-Bu)
Becker, Eva,Mereiter, Kurt,Puchberger, Michael,Schmid, Roland,Kirchner, Karl
, p. 2124 - 2133 (2008/10/08)
The oxidative coupling of alkynes is investigated as promoted by the half-sandwich compound [RuCp(SbR3)(CH3CN)2]PF6 (R = Ph, n-Bu). There are various ways by which the initially formed electrophilic metallacyclopentatriene complex rearranges to a stable product. In the case where the alkyne disposes of an α-alkyl substituent, intramolecular 1,2 hydrogen migration leads to a butadienyl carbene complex as obtained by using 2,8-decadiyne or HC≡CCH2R′ (R′ = n-Pr, Ph, OH). A conceivable mechanism for this reaction sequence is established by means of DFT/B3LYP calculations. In line with experiment, the existence of two isomeric butadienyl carbene complexes is proposed. In the case of R′ = Ph and OH the butadienyl carbene is not the final product but rearranges to give η3-allyl-vinyl and η3-allyl-acyl complexes. In the absence of an α-alkyl substituent as for HC≡CC6H9, HC≡CC6H10-OH, and HC≡CCMe2OH, η3-butadienyl-vinyl complexes are formed. Finally, from the alkynes HC≡CPh, HC≡CBut, and HC≡CSiMe3 no tractable materials are obtained.