Journal article
New Chiral Amide Ligands Derived from (±)- trans -1,2-Diaminocyclohexane. Applications in Titanium(IV) Chemistry
Organometallics, Vol.16(7), pp.1392-1400
04/01/1997
DOI: 10.1021/om960939m
Abstract
Titanium(IV) hydrocarbyl compounds containing chiral bis(amide) ligands derived from (±)-trans-1,2-(NHSiR3)2-cyclohexanes (6a−c: SiR3 = SiMe3 (a), SiMe2Ph (b), SiMePh2 (c) are described. The reaction of (±)-trans-1,2-diaminocyclohexane with SiR3Cl and NEt3 affords diamines 6a−c in 60−80% yield. Double deprotonation of 6a−c with 2 equiv of n-BuLi yields the dilithio salts Li2[(±)-trans-1,2-(NSiR3)2-cyclohexane] (7a−c) in 70−97% yield. The reaction of 7a,b with TiCl4(THF)2 in toluene yields mixtures of {(±)-trans-1,2-(NSiR3)2-cyclohexane}TiCl2 (8a,b) and bis(ligand) complexes {trans-1,2-(NSiR3)2-cyclohexane}2Ti (9a,b; mixture of diastereomers). The reaction of 7c with TiCl4 yields {(±)-trans-1,2-(NSiMePh2)2-cyclohexane}TiCl2 (8c; 15% isolated yield). The reaction of 6a,b and Ti(CH2Ph)4 yields {(±)-trans-1,2-(NSiR3)2-cyclohexane}Ti(CH2Ph)2 (10a,b) cleanly, but these species are difficult to isolate due to their high solubility. Iodinolysis of 10a,b with I2 yields {(±)-trans-1,2-(NSiR3)2-cyclohexane}TiI2 (11a,b) in 60−80% isolated yield. 11a,b can be prepared in 60−80% isolated yield (vs Ti(CH2Ph)4) in a “one-pot” reaction by treatment of Ti(CH2Ph)4 with 6a,b followed by iodinolysis. The dimethyl and diphenyl derivatives {(±)-trans-1,2-(NSiR3)2-cyclohexane}TiMe2 (12a,b) and {(±)-trans-1,2-(NSiR3)2-cyclohexane}TiPh2 (13a,b) are prepared by the reaction of 11a,b and RMgX reagents. X-ray crystallographic analyses establish that 10a and 11a have distorted tetrahedral structures with small N−Ti−N angles (ca. 92°) and large X−Ti−X angles (ca. 116°).
Details
- Title: Subtitle
- New Chiral Amide Ligands Derived from (±)- trans -1,2-Diaminocyclohexane. Applications in Titanium(IV) Chemistry
- Creators
- Barbara Tsuie - University of IowaDale C. Swenson - University of IowaRichard F. Jordan - University of IowaJeffrey L. Petersen - West Virginia University
- Resource Type
- Journal article
- Publication Details
- Organometallics, Vol.16(7), pp.1392-1400
- DOI
- 10.1021/om960939m
- ISSN
- 0276-7333
- eISSN
- 1520-6041
- Language
- English
- Date published
- 04/01/1997
- Academic Unit
- Chemistry
- Record Identifier
- 9984622746502771
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