TY - JOUR
T1 - Oxapentadienyl—Iridium—Phosphine Chemistry. Synthesis of Oxygen-Containing Iridacycles via CH Bond Activation
AU - Bleeke, John R.
AU - Haile, Tesfamichael
AU - New, Pamela R.
AU - Chiang, Michael Y.
PY - 1993
Y1 - 1993
N2 - The reactions of (Cl)Ir(PR3)3 (R = Me, Et) with potassium oxapentadienide, potassium 4-methyl-5-oxapentadienide, and potassium 2,4-dimethyl-5-oxapentadienide have been investigated. Treatment of (Cl)Ir(PMe3)3 with potassium oxapentadienide initially produces ((1,2,5-η)-5-oxapentadienyl)Ir(PMe3)3 (1), which rapidly rearranges to ((l,2,3-η)-5-oxapentadienyl)Ir(PMe3)3 (2a). When refluxed in tetrahydrofuran, 2a undergoes metal-centered activation of the aldehydic CH bond (C4H) to produce the iridacyclopentenone complex fac-[formula omitted] (3). Treatment of (Cl)Ir(PEt3)3 with potassium oxapentadienide yields the iridapyran complex mer-[formula omitted] (4) via activation of a CH bond on the C-terminus (Cl) of an O-bound η1-oxapentadienyl ligand. Upon stirring in tetrahydrofuran solution, 4 gradually converts to the iridacyclopentenone complex foc-[formula omitted] (5). Treatment of (Cl)Ir(PMe3)3 with potassium 4-methyl-5-oxapentadienide produces ((l,2,5-η)-4-methyl-5-oxapentadienyl)Ir(PMe3)3 (6). However, upon refluxing in tetrahydrofuran, this species undergoes CH bond activation at C2 of the 4-methyl-5-oxapentadienyl ligand, generating the iridaoxacyclopentene derivative mer-[formula omitted] (7). Treatment of (Cl)Ir(PEt3)3 with potassium 4-methyl-5-oxapentadienide initially produces the 4-methyliridapyran complex mer-[formula omitted] (8) via ClH bond activation, but in refluxing tetrahydrofuran this species isomerizes to the PEt3 analogue of 7, mer-[formula omitted] (9). Finally, treatment of (Cl)Ir(PMe3)3 or (Cl)Ir(PEt3)3 with potassium 2,4-dimethyl-5-oxapentadienide, followed by stirring for several days in tetrahydrofuran at room temperature, leads cleanly to the production of the 2,4-dimethyliridapyran complexes mer-[formula omitted]. These species undergo no further rearrangements, even upon refluxing in tetrahydrofuran. Molecular structures of ((1,2,3-η)-5-oxapentadienyl)Ir(PMe2Ph)3 (2b), fac-[formula omitted] (5), and mer-[formula omitted] (9) have been determined by single-crystal X-ray diffraction studies. Crystal structure data for these compounds are as follows: 2b, triclinic, P1̅, a = 9.506 (2) Å, b = 17.219 (4) Å, c = 18.546 (5) Å, α = 111.14 (2)°, β = 97.62 (2)°, γ = 91.49 (2)°, V = 2797.4 (12) Å3, Z = 4, R = 0.034 for 6227 reflections with I > 3σ(I); 5, orthorhombic, Pna21, a = 15.271 (4) Å,b = 11.401 (3) Å, c = 15.473 (4) Å,R = 0.025 for 3363 reflections with I > 3σ(I); 9, triclinic, P1̅, a = 9.396 (2) Å, b = 10.742 (2) Å, c = 15.725 (5) Å, a = 77.88 (2)°, β = 77.52 (2)°, γ = 68.09 (2)°, V = 1423.0 (6) Å3, Z = 2, R = 0.018 for 4299 reflections with I > 3σ(I).
AB - The reactions of (Cl)Ir(PR3)3 (R = Me, Et) with potassium oxapentadienide, potassium 4-methyl-5-oxapentadienide, and potassium 2,4-dimethyl-5-oxapentadienide have been investigated. Treatment of (Cl)Ir(PMe3)3 with potassium oxapentadienide initially produces ((1,2,5-η)-5-oxapentadienyl)Ir(PMe3)3 (1), which rapidly rearranges to ((l,2,3-η)-5-oxapentadienyl)Ir(PMe3)3 (2a). When refluxed in tetrahydrofuran, 2a undergoes metal-centered activation of the aldehydic CH bond (C4H) to produce the iridacyclopentenone complex fac-[formula omitted] (3). Treatment of (Cl)Ir(PEt3)3 with potassium oxapentadienide yields the iridapyran complex mer-[formula omitted] (4) via activation of a CH bond on the C-terminus (Cl) of an O-bound η1-oxapentadienyl ligand. Upon stirring in tetrahydrofuran solution, 4 gradually converts to the iridacyclopentenone complex foc-[formula omitted] (5). Treatment of (Cl)Ir(PMe3)3 with potassium 4-methyl-5-oxapentadienide produces ((l,2,5-η)-4-methyl-5-oxapentadienyl)Ir(PMe3)3 (6). However, upon refluxing in tetrahydrofuran, this species undergoes CH bond activation at C2 of the 4-methyl-5-oxapentadienyl ligand, generating the iridaoxacyclopentene derivative mer-[formula omitted] (7). Treatment of (Cl)Ir(PEt3)3 with potassium 4-methyl-5-oxapentadienide initially produces the 4-methyliridapyran complex mer-[formula omitted] (8) via ClH bond activation, but in refluxing tetrahydrofuran this species isomerizes to the PEt3 analogue of 7, mer-[formula omitted] (9). Finally, treatment of (Cl)Ir(PMe3)3 or (Cl)Ir(PEt3)3 with potassium 2,4-dimethyl-5-oxapentadienide, followed by stirring for several days in tetrahydrofuran at room temperature, leads cleanly to the production of the 2,4-dimethyliridapyran complexes mer-[formula omitted]. These species undergo no further rearrangements, even upon refluxing in tetrahydrofuran. Molecular structures of ((1,2,3-η)-5-oxapentadienyl)Ir(PMe2Ph)3 (2b), fac-[formula omitted] (5), and mer-[formula omitted] (9) have been determined by single-crystal X-ray diffraction studies. Crystal structure data for these compounds are as follows: 2b, triclinic, P1̅, a = 9.506 (2) Å, b = 17.219 (4) Å, c = 18.546 (5) Å, α = 111.14 (2)°, β = 97.62 (2)°, γ = 91.49 (2)°, V = 2797.4 (12) Å3, Z = 4, R = 0.034 for 6227 reflections with I > 3σ(I); 5, orthorhombic, Pna21, a = 15.271 (4) Å,b = 11.401 (3) Å, c = 15.473 (4) Å,R = 0.025 for 3363 reflections with I > 3σ(I); 9, triclinic, P1̅, a = 9.396 (2) Å, b = 10.742 (2) Å, c = 15.725 (5) Å, a = 77.88 (2)°, β = 77.52 (2)°, γ = 68.09 (2)°, V = 1423.0 (6) Å3, Z = 2, R = 0.018 for 4299 reflections with I > 3σ(I).
UR - https://www.scopus.com/pages/publications/0001225996
U2 - 10.1021/om00026a039
DO - 10.1021/om00026a039
M3 - Article
AN - SCOPUS:0001225996
SN - 0276-7333
VL - 12
SP - 517
EP - 528
JO - Organometallics
JF - Organometallics
IS - 2
ER -