Reaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage.
We report a range of new transformations of the diamide-amine supported Ti==NNPh(2) functional group with a variety of unsaturated substrates, along with DFT studies of the key mechanisms. Reaction of [Ti(N(2)N(py))(NNPh(2))(py)] (4, N(2)N(py)=(2-NC(5)H(4))CMe(CH(2)NSiMe(3))(2); py=pyridine) with Me...
| Principais autores: | , , , , , |
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| Formato: | Journal article |
| Idioma: | English |
| Publicado em: |
2010
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| _version_ | 1826294553506742272 |
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| author | Schofield, A Nova, A Selby, J Schwarz, A Clot, E Mountford, P |
| author_facet | Schofield, A Nova, A Selby, J Schwarz, A Clot, E Mountford, P |
| author_sort | Schofield, A |
| collection | OXFORD |
| description | We report a range of new transformations of the diamide-amine supported Ti==NNPh(2) functional group with a variety of unsaturated substrates, along with DFT studies of the key mechanisms. Reaction of [Ti(N(2)N(py))(NNPh(2))(py)] (4, N(2)N(py)=(2-NC(5)H(4))CMe(CH(2)NSiMe(3))(2); py=pyridine) with MeCN gave the dimeric species [Ti(2)(N(2)N(py))(2){μ-NC(Me)(NNPh(2))}(2)] through a [2+2] cycloaddition process. Reaction of 4 or [Ti(N(2)N(Me))(NNPh(2))(py)] (5, N(2)N(Me)=MeN(CH(2)CH(2)NSiMe(3))(2)) with fluorinated benzonitriles gave the terminal hydrazonamide complexes [Ti(N(2)N(R)){NC(Ar(F(x) ))NNPh(2)}(py)] (R=py or Me; Ar(F(x) )=2,6-C(6)H(3)F(2) or C(6)F(5)). DFT studies showed that this proceeds through an overall [2+2] cycloaddition-reverse cycloaddition, resulting in net insertion of Ar(F(x) )CN into the Ti==N(α) bonds of the respective hydrazides. Reaction of 4 with a mixture of MeCN and PhCCMe gave the metallacycle [Ti(N(2)N(py)){NC(Me)C(Ph)C(Me)NNPh(2)}] by sequential coupling of Ti==NNPh(2) with PhCCMe and then MeCN. A related product, [Ti(N(2)N(py)){NC(Me)C(Ar(F))C(H)NNPh(2)}], was formed by insertion of MeCN into the Ti--C bond of the isolated azatitanacyclobutene [Ti(N(2)N(py)){N(NPh(2))C(H)C(Ar(F))}] (Ar(F)=3-C(6)H(4)F). Reaction of 4 with two equivalents of B(Ar(F(5) ))(3) (Ar(F(5) )=C(6)F(5)) formed the zwitterionic borate [Ti(N(2)N(py)){η(2)-N(NPh(2))B(Ar(F(5) ))(3)}] by electrophilic attack at N(α). Compounds 4 and 5 reacted with tBuNC and/or XylNC (Xyl=2,6-C(6)H(3)Me(2)) to give the N(α)--N(β) bond cleavage products, [Ti(N(2)N(R))(NCNR')(NPh(2))] (R=py or Me; R'=tBu or Xyl), containing metallated carbodiimide ligands. DFT studies of these reactions found an initial addition of RNC across Ti==N(α) followed by N(β) coordination, and finally complete N(α) transfer from the NNPh(2) to the RNC fragment. Reaction of 5 with Ar'NCE (E=O, S, Se; Ar'=2,6-C(6)H(3)iPr(2)) gave the [2+2] cycloaddition products [Ti(N(2)N(Me)){N(NPh(2))C(NAr')O}(py)] and [Ti(N(2)N(Me)){N(NPh(2))C(NAr')E}] (E=S or Se), which did not undergo further transformation of the Ti--N--NPh(2) moiety. |
| first_indexed | 2024-03-07T03:47:26Z |
| format | Journal article |
| id | oxford-uuid:bffc8069-e49e-49dd-97c0-c1e186b5bd03 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:47:26Z |
| publishDate | 2010 |
| record_format | dspace |
| spelling | oxford-uuid:bffc8069-e49e-49dd-97c0-c1e186b5bd032022-03-27T05:51:28ZReaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:bffc8069-e49e-49dd-97c0-c1e186b5bd03EnglishSymplectic Elements at Oxford2010Schofield, ANova, ASelby, JSchwarz, AClot, EMountford, PWe report a range of new transformations of the diamide-amine supported Ti==NNPh(2) functional group with a variety of unsaturated substrates, along with DFT studies of the key mechanisms. Reaction of [Ti(N(2)N(py))(NNPh(2))(py)] (4, N(2)N(py)=(2-NC(5)H(4))CMe(CH(2)NSiMe(3))(2); py=pyridine) with MeCN gave the dimeric species [Ti(2)(N(2)N(py))(2){μ-NC(Me)(NNPh(2))}(2)] through a [2+2] cycloaddition process. Reaction of 4 or [Ti(N(2)N(Me))(NNPh(2))(py)] (5, N(2)N(Me)=MeN(CH(2)CH(2)NSiMe(3))(2)) with fluorinated benzonitriles gave the terminal hydrazonamide complexes [Ti(N(2)N(R)){NC(Ar(F(x) ))NNPh(2)}(py)] (R=py or Me; Ar(F(x) )=2,6-C(6)H(3)F(2) or C(6)F(5)). DFT studies showed that this proceeds through an overall [2+2] cycloaddition-reverse cycloaddition, resulting in net insertion of Ar(F(x) )CN into the Ti==N(α) bonds of the respective hydrazides. Reaction of 4 with a mixture of MeCN and PhCCMe gave the metallacycle [Ti(N(2)N(py)){NC(Me)C(Ph)C(Me)NNPh(2)}] by sequential coupling of Ti==NNPh(2) with PhCCMe and then MeCN. A related product, [Ti(N(2)N(py)){NC(Me)C(Ar(F))C(H)NNPh(2)}], was formed by insertion of MeCN into the Ti--C bond of the isolated azatitanacyclobutene [Ti(N(2)N(py)){N(NPh(2))C(H)C(Ar(F))}] (Ar(F)=3-C(6)H(4)F). Reaction of 4 with two equivalents of B(Ar(F(5) ))(3) (Ar(F(5) )=C(6)F(5)) formed the zwitterionic borate [Ti(N(2)N(py)){η(2)-N(NPh(2))B(Ar(F(5) ))(3)}] by electrophilic attack at N(α). Compounds 4 and 5 reacted with tBuNC and/or XylNC (Xyl=2,6-C(6)H(3)Me(2)) to give the N(α)--N(β) bond cleavage products, [Ti(N(2)N(R))(NCNR')(NPh(2))] (R=py or Me; R'=tBu or Xyl), containing metallated carbodiimide ligands. DFT studies of these reactions found an initial addition of RNC across Ti==N(α) followed by N(β) coordination, and finally complete N(α) transfer from the NNPh(2) to the RNC fragment. Reaction of 5 with Ar'NCE (E=O, S, Se; Ar'=2,6-C(6)H(3)iPr(2)) gave the [2+2] cycloaddition products [Ti(N(2)N(Me)){N(NPh(2))C(NAr')O}(py)] and [Ti(N(2)N(Me)){N(NPh(2))C(NAr')E}] (E=S or Se), which did not undergo further transformation of the Ti--N--NPh(2) moiety. |
| spellingShingle | Schofield, A Nova, A Selby, J Schwarz, A Clot, E Mountford, P Reaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage. |
| title | Reaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage. |
| title_full | Reaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage. |
| title_fullStr | Reaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage. |
| title_full_unstemmed | Reaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage. |
| title_short | Reaction Site Diversity in the Reactions of Titanium Hydrazides with Organic Nitriles, Isonitriles and Isocyanates: Ti==N(α) Cycloaddition, Ti==N(α) Insertion and N(α)--N(β) Bond Cleavage. |
| title_sort | reaction site diversity in the reactions of titanium hydrazides with organic nitriles isonitriles and isocyanates ti n α cycloaddition ti n α insertion and n α n β bond cleavage |
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