Novel Nine-Membered Titanaheterocycles – Structure, ab initio Calculations, and Preparative Use towards the Selective Synthesis of Substituted Cyclopentanols

Hampel, Frank; Hommes, Nicolaas J. R. van Eikema; Hoops, Sven; Maaref, Faramarz; Schobert, Rainer

doi:10.1002/(sici)1099-0682(199809)1998:9<1253::aid-ejic1253>3.0.co;2-h

Cited by 7 publications

(1 citation statement)

References 49 publications

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“…Such large angles are incompatible with five- or six-membered rings, yet the eight-membered rings here allow relatively large angles of 149° on average, only modestly more acute than the 165° angles seen in the unconstrained phenoxides 1 and 2 . Indeed, even larger chelate rings containing alkoxides are known for titanium and show little evidence of strain . Complex 4 provides a dramatic example of how this preference for chelation can even outweigh the well-known predilection of the nitrilotriethoxide ligand to adopt a tetradentate binding mode.…”

Section: Discussionmentioning

confidence: 99%

Titanatranes Derailed: Static and Dynamic Triethanolamine Slippage Induced by Polyphenoxide Chelation

Maestri

Brown

2004

Inorg. Chem.

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Aryloxytitanatranes [N(CH(2)CH(2)O)(3)]Ti[OC(6)H(2)-2,4-(t)()Bu(2)-6-CHPh(3)(-)(n)()(C(6)H(2)-3,5-(t)()Bu(2)-2-OH)(n)(-)(1)] (1, n = 1; 2, n = 2; 3, n = 3) containing aryloxides derived from substituted triphenylmethanes are formed in high yield in the reactions of the corresponding phenols with tert-butoxytitanatrane [N(CH(2)CH(2)O)(3)]Ti(O(t)()Bu). The aryloxytitanatranes adopt monomeric, trigonal bipyramidal structures, as confirmed by X-ray crystallography for 1 and 2. The compounds with pendant phenol groups display fluxional behavior due to interchange of the bound phenoxide with the free phenol groups, most likely via a mechanism involving displacement of one arm of the nitrilotriethoxide by the dangling phenol group. The amidotitanatrane [[N(CH(2)CH(2)O)(3)]Ti(NEt(2))](2) reacts with the bisphenol PhCH(C(6)H(2)-3,5-(t)()Bu(2)-2-OH)(2) to give a crystallographically characterized fully metalated cyclic octatitanium complex of the formula [PhCH(C(6)H(2)-3,5-(t)()Bu(2)-2-O)(2)Ti(2)[(OCH(2)CH(2))(3)N](2)](4) (4). The structure of 4 reveals a metallamacrocycle (minimum ring size = 28 members) consisting of four repeating unsymmetrical dititanium units. In each dititanium unit, there is an unprecedented slippage of the nitrilotriethoxide ligand such that both triethanolamine nitrogens coordinate to only one of the two titaniums, while the bisphenoxide is coordinated only to the other titanium. The propensity of the polyphenoxide ligands to chelate is attributed to favorable pi-bonding interactions attainable in the eight-membered chelate rings.

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Section: Discussionmentioning

confidence: 99%

Titanatranes Derailed: Static and Dynamic Triethanolamine Slippage Induced by Polyphenoxide Chelation

Maestri

Brown

2004

Inorg. Chem.

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Synthesis of Metal Enolato Complexes

Vicente

2010

Patai's Chemistry of Functional Groups

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Introduction Synthesis from Ketones, Aldehydes and Esters Synthesis from Ketenes, Isocyanates and Acyl Halides Synthesis from Carbon Monoxide and Carbonyl Complexes Synthesis via Cleavage of Ethers and Related Compounds Synthesis from Oxo, Hydroxo or Alkoxo Complexes Oxygenation Reactions Miscellaneous Reactions Acknowledgments

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Bonding in titanocenyl complexes containing O,O′‐cyclic ligands

Conradie

2009

Int J of Quantum Chemistry

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Novel Nine-Membered Titanaheterocycles – Structure, ab initio Calculations, and Preparative Use towards the Selective Synthesis of Substituted Cyclopentanols

Cited by 7 publications

References 49 publications

Titanatranes Derailed: Static and Dynamic Triethanolamine Slippage Induced by Polyphenoxide Chelation

Titanatranes Derailed: Static and Dynamic Triethanolamine Slippage Induced by Polyphenoxide Chelation

Synthesis of Metal Enolato Complexes

Bonding in titanocenyl complexes containing O,O′‐cyclic ligands

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