Titanium complexes with chiral amino alcohol ligands: Synthesis and structure of complexes related to hydroamination catalysts

Juliette R. Petersen; Jessica M. Hoover; W. Scott Kassel; Arnold L. Rheingold; Adam R. Johnson

doi:10.1016/j.ica.2004.09.051

Titanium complexes with chiral amino alcohol ligands: Synthesis and structure of complexes related to hydroamination catalysts

Juliette R. Petersen, Jessica M. Hoover, W. Scott Kassel, Arnold L. Rheingold, Adam R. Johnson

Research output: Contribution to journal › Article › peer-review

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Abstract

Titanium complexes with chiral amino alcohol ligands are useful precatalysts for the intramolecular hydroamination of aminoallenes. They can be synthesized via protonolysis of titanium dimethylamide starting materials with the free ligand. In most cases, the resulting materials are not isolable due to their oily nature. However, several complexes were prepared in pure form and isolated as solid materials. [Ti(Cl)(NMe₂)(-OCH₂CH(Ph) N(CHMe₂)-]₂ was prepared at room temperature from TiCl(NMe₂)₃ and the corresponding N-substituted d-amino alcohol; the dimeric nature of the complex was established by X-ray crystallography. [Ti(NMe₂)₂(-OCH₂CH(Ph)N(2-Ad)- )]₂ (2-Ad = 2-Adamantyl) was prepared from Ti(NMe₂) ₄ and the corresponding N-substituted l-amino alcohol after prolonged heating. An intermediate complex that could not be purified or isolated is believed to be Ti(NMe₂)₃(-OCH₂CH(Ph)NH(2-Ad)). Two complexes with the composition TiCl₂(-OCH₂CH(R*) N(CHMe₂)-)(HNMe₂) (where R* = CH₂Ph or CHMe₂) were prepared at room temperature by protonolysis of TiCl ₂(NMe₂)₂ with the corresponding N-substituted l-amino alcohols. These two complexes exhibit dynamic behavior on the NMR timescale that is believed to be a dimer-monomer equilibrium, but they decompose at elevated temperatures.

Original language	English (US)
Pages (from-to)	687-694
Number of pages	8
Journal	Inorganica Chimica Acta
Volume	358
Issue number	3
DOIs	https://doi.org/10.1016/j.ica.2004.09.051
State	Published - Feb 10 2005
Externally published	Yes

Bibliographical note

Funding Information:
The authors gratefully acknowledge the financial support of the Harvey Mudd College Research Fund, the Donors of the American Chemical Society Petroleum Research Fund and the National Science Foundation (REU-CHE-0097262).

Keywords

Amino alcohol complexes
Crystal structures
Titanium

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10.1016/j.ica.2004.09.051

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title = "Titanium complexes with chiral amino alcohol ligands: Synthesis and structure of complexes related to hydroamination catalysts",

abstract = "Titanium complexes with chiral amino alcohol ligands are useful precatalysts for the intramolecular hydroamination of aminoallenes. They can be synthesized via protonolysis of titanium dimethylamide starting materials with the free ligand. In most cases, the resulting materials are not isolable due to their oily nature. However, several complexes were prepared in pure form and isolated as solid materials. [Ti(Cl)(NMe2)(-OCH2CH(Ph) N(CHMe2)-]2 was prepared at room temperature from TiCl(NMe2)3 and the corresponding N-substituted d-amino alcohol; the dimeric nature of the complex was established by X-ray crystallography. [Ti(NMe2)2(-OCH2CH(Ph)N(2-Ad)- )]2 (2-Ad = 2-Adamantyl) was prepared from Ti(NMe2) 4 and the corresponding N-substituted l-amino alcohol after prolonged heating. An intermediate complex that could not be purified or isolated is believed to be Ti(NMe2)3(-OCH2CH(Ph)NH(2-Ad)). Two complexes with the composition TiCl2(-OCH2CH(R*) N(CHMe2)-)(HNMe2) (where R* = CH2Ph or CHMe2) were prepared at room temperature by protonolysis of TiCl 2(NMe2)2 with the corresponding N-substituted l-amino alcohols. These two complexes exhibit dynamic behavior on the NMR timescale that is believed to be a dimer-monomer equilibrium, but they decompose at elevated temperatures.",

keywords = "Amino alcohol complexes, Crystal structures, Titanium",

author = "Petersen, {Juliette R.} and Hoover, {Jessica M.} and Kassel, {W. Scott} and Rheingold, {Arnold L.} and Johnson, {Adam R.}",

note = "Funding Information: The authors gratefully acknowledge the financial support of the Harvey Mudd College Research Fund, the Donors of the American Chemical Society Petroleum Research Fund and the National Science Foundation (REU-CHE-0097262). ",

year = "2005",

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doi = "10.1016/j.ica.2004.09.051",

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TY - JOUR

T1 - Titanium complexes with chiral amino alcohol ligands

T2 - Synthesis and structure of complexes related to hydroamination catalysts

AU - Petersen, Juliette R.

AU - Hoover, Jessica M.

AU - Kassel, W. Scott

AU - Rheingold, Arnold L.

AU - Johnson, Adam R.

N1 - Funding Information: The authors gratefully acknowledge the financial support of the Harvey Mudd College Research Fund, the Donors of the American Chemical Society Petroleum Research Fund and the National Science Foundation (REU-CHE-0097262).

PY - 2005/2/10

Y1 - 2005/2/10

N2 - Titanium complexes with chiral amino alcohol ligands are useful precatalysts for the intramolecular hydroamination of aminoallenes. They can be synthesized via protonolysis of titanium dimethylamide starting materials with the free ligand. In most cases, the resulting materials are not isolable due to their oily nature. However, several complexes were prepared in pure form and isolated as solid materials. [Ti(Cl)(NMe2)(-OCH2CH(Ph) N(CHMe2)-]2 was prepared at room temperature from TiCl(NMe2)3 and the corresponding N-substituted d-amino alcohol; the dimeric nature of the complex was established by X-ray crystallography. [Ti(NMe2)2(-OCH2CH(Ph)N(2-Ad)- )]2 (2-Ad = 2-Adamantyl) was prepared from Ti(NMe2) 4 and the corresponding N-substituted l-amino alcohol after prolonged heating. An intermediate complex that could not be purified or isolated is believed to be Ti(NMe2)3(-OCH2CH(Ph)NH(2-Ad)). Two complexes with the composition TiCl2(-OCH2CH(R*) N(CHMe2)-)(HNMe2) (where R* = CH2Ph or CHMe2) were prepared at room temperature by protonolysis of TiCl 2(NMe2)2 with the corresponding N-substituted l-amino alcohols. These two complexes exhibit dynamic behavior on the NMR timescale that is believed to be a dimer-monomer equilibrium, but they decompose at elevated temperatures.

AB - Titanium complexes with chiral amino alcohol ligands are useful precatalysts for the intramolecular hydroamination of aminoallenes. They can be synthesized via protonolysis of titanium dimethylamide starting materials with the free ligand. In most cases, the resulting materials are not isolable due to their oily nature. However, several complexes were prepared in pure form and isolated as solid materials. [Ti(Cl)(NMe2)(-OCH2CH(Ph) N(CHMe2)-]2 was prepared at room temperature from TiCl(NMe2)3 and the corresponding N-substituted d-amino alcohol; the dimeric nature of the complex was established by X-ray crystallography. [Ti(NMe2)2(-OCH2CH(Ph)N(2-Ad)- )]2 (2-Ad = 2-Adamantyl) was prepared from Ti(NMe2) 4 and the corresponding N-substituted l-amino alcohol after prolonged heating. An intermediate complex that could not be purified or isolated is believed to be Ti(NMe2)3(-OCH2CH(Ph)NH(2-Ad)). Two complexes with the composition TiCl2(-OCH2CH(R*) N(CHMe2)-)(HNMe2) (where R* = CH2Ph or CHMe2) were prepared at room temperature by protonolysis of TiCl 2(NMe2)2 with the corresponding N-substituted l-amino alcohols. These two complexes exhibit dynamic behavior on the NMR timescale that is believed to be a dimer-monomer equilibrium, but they decompose at elevated temperatures.

KW - Amino alcohol complexes

KW - Crystal structures

KW - Titanium

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VL - 358

SP - 687

EP - 694

JO - Inorganica Chimica Acta

JF - Inorganica Chimica Acta

IS - 3

ER -

Titanium complexes with chiral amino alcohol ligands: Synthesis and structure of complexes related to hydroamination catalysts

Abstract

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