Synthesis and reactions of acyl(cyclohexadienyl)manganates

John B. Sheridan, Ranbir S. Padda, Karen Chaffee, Chenjie Wang, Yazhong Huang, Roger Lalancette

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

The cyclohexadienyl complexes [Mn(η5-C6H6R1)(CO)3] 1 (R1 = exo-H, Me or C6H4Me-4) react with LiR2 (R2 = Me or Ph) to give acylmetalates [Li(OEt2)][Mn(η5-C6H6R 1)(CO)2{C(O)R2}] 2. Complex 2 (R1 = Me, R2 = Ph) has been characterised by an X-ray crystallography study: orthorhombic, space group P212121, a = 9.113(2), b = 14.491(8), c = 32.803(9) Å, R = 0.064 for 1458 independent reflections. Protonation of 2 with HBF4·Et2O induces an aryl- or alkyl-group transfer to the endo face of the cyclohexadienyl ring yielding the new agostic cyclohexenyl complexes [Mn(η3:CHC6H7R1R 2)(CO)3] 3. The cyclohexenyl ligands can be decomplexed from the metal via treatment of 3 with 1,2-bis-(diphenylphosphino)ethane (dppe) in tetrahydrofuran to afford mixtures of substituted cyclohexa-1,3-dienes and [MnH(CO)3(dppe)]. The acylmetalates 2 react with [NO][BF4] at -78 °C to give [Mn(η5-C6H6R 1)(CO)(NO){C(O)R2}] which decompose at room temperature to form the trans-disubstituted acylcyclohexadienes C6H6R1[C(O)R2]. Reaction of 2 with electrophiles SiMe3Cl, [Me3O][BF4] or [Et3O][BF4] results in O alkylation and formation of stable carbene complexes [Mn(η5-C6H6R1)(CO) 2{C(OE)R2}] (E = SiMe3, Me or Et).

Original languageEnglish (US)
Pages (from-to)1539-1548
Number of pages10
JournalJournal of the Chemical Society, Dalton Transactions
Issue number9
DOIs
StatePublished - 1992

All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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