Reactions of electrophilic alkynes with some iron and tungsten sulphur, selenium, and arsenic complexes

Laurence Carlton, Jack L. Davidson, Mahmoud Shiralian

Research output: Contribution to journalArticle

Abstract

Reactions of [Fe(AsMe2)(CO)2(?5-C5H5)], [W(AsMe2)(CO)3(?5-C5H 5)], and [W(SR') (CO)3(?5C5H5)] with activated alkynes CF3C=CCF3 and/or MeO2CC=CCO2 Me afford metallacyclic complexes [Fe{C(O)C(CO2Me)=C(CO2Me)AsMe2}(CO)(? 5-C5H5)], [W{C(O)C(R)=C(R)AsMe2}(CO)2(?5C5H 5)] (R = CF3 or CO2Me), and [W{C(O)C(R)=C(R)SR'}(CO)2(?5-C5H 5)] (R = CF3, R' = Prn; R = CO2Me, R' = Pri or Prn) or the ?2-vinyl complex [W{?2-C(CF3)C(CF3)C(O)SR'}(CO) 2(?5-C5H5)] when R' = Pri. The photolytic reaction of [W(SePh)(CO)3(?5-C5H5)] with CF3C=CCF3 gives an alkyne derivative [W(SePh)(CO)(CF3C=CCF3)(?5-C 5H5)]. A similar species [W(SC6H4Me-4)(CO)(CF3C=CCF3) (?5-C5H5)] was obtained from the thermal reaction of [W(SC6H4Me-4)(CO)3(?5-C 5H5)] with CF3C=CCF3 via metallacyclic [W{C(O)C(CF3)=C(CF3) SC6H4Me-4}(CO)2(?5-C 5H5)] and ?2-vinyl [W{?2-C(CF3)C(CF3)C(O)SC6H 4Me-4}(CO)2(?5-C5H5)] intermediates. In contrast, [W{C(O)C(CF3)=C(CF3)SPrn}(CO) 2(?5-C5H5)] isomerises via an ?2-vinyl analogue into the S-bonded vinyl ketone complex [W{C(CF3)=C(CF3)C(O)SPrn}(CO) 2(?5-C5H5)] as a result of a 1,3 SR' shift across the metallacyclic ring. Such a shift is also observed on thermal isomerisation of [W{C(O)C(C02Me)=C(CO2Me)SR'}(CO) 2(?5-C5H5)] (R' = Me or Pri) but this proceeds via a s-vinyl intermediate [W{C(CO2Me)=C(CO2Me)SR'}(CO)3(? 5-C5H5)] to give both S- and O-metallated isomeric vinyl ketone derivatives. The mechanism of the shift is discussed in terms of three alternative pathways which are determined by the nature of the group R on the alkyne. The ?2-vinyl complexes [W{?2-C(CF3)C(CF3)C(O)SR'}(CO) 2(?5-C5H5)] (R' = Me or Pri), on reaction with two-electron donor ligands L = CO, CNBut, PMe2Ph, or P(OMe)3, afford ?3-lactone derivatives [W{?3-C(CF3)C(CF 3)C(SR')OC(O)}(CO)L(?5-C5H 5)] as a result of cyclisation of the ?2-vinyl ligand with a co-ordinated carbonyl group.

Original languageEnglish
Pages (from-to)1577-1586
Number of pages10
JournalJournal of the Chemical Society, Dalton Transactions
Issue number8
DOIs
Publication statusPublished - 1986

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