Ruthenium-Mediated Cyclometalation Reactions of Allene and Allylphosphine CC Bonds: Synthesis of κ(<i>P</i>),η<sup>4</sup>-(Hexa-2,5-dien-1-yl)diphenylphosphine–Ruthenium(II) Complexes
- Publication date
- Publisher
Abstract
The cyclopentadienyl-containing complex [Ru(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)(MeCN){κ<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)-Ph<sub>2</sub>PCH<sub>2</sub>CHCH<sub>2</sub>}][PF<sub>6</sub>] (<b>1</b>) reacts with allenes, giving regioselectively the η<sup>2</sup>-allene complexes [Ru(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)(MeCN){κ(<i>P</i>)-Ph<sub>2</sub>PCH<sub>2</sub>CHCH<sub>2</sub>}(η<sup>2</sup>-CH<sub>2</sub>CCR<sup>1</sup>R<sup>2</sup>)][PF<sub>6</sub>] [R<sup>1</sup> = R<sup>2</sup> = Me (<b>3</b>); R<sup>1</sup> = H, R<sup>2</sup> = Ph (<b>4</b>); R<sup>1</sup>R<sup>2</sup> = −(CH<sub>2</sub>)<sub>5</sub>– (<b>5</b>)]. On the other hand, the reaction of the pentamethylcyclopentadienyl-containing complex [Ru(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)(MeCN){κ<sup>3</sup>(<i>P</i>,<i>C</i>,<i>C</i>)-Ph<sub>2</sub>PCH<sub>2</sub>CHCH<sub>2</sub>}][OTf] (<b>2</b>) with allenes yields regio- and stereoselectively the complexes [Ru(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>){κ(<i>P</i>),η<sup>4</sup>-Ph<sub>2</sub>PCH<sub>2</sub>CHCHC(R<sup>1</sup>R<sup>2</sup>)CHCH<sub>2</sub>}][OTf] [R<sup>1</sup> = R<sup>2</sup> = Me (<b>6</b>); R<sup>1</sup> = H, R<sup>2</sup> = Ph (<b>7</b>); R<sup>1</sup>R<sup>2</sup> = −(CH<sub>2</sub>)<sub>5</sub>– (<b>8</b>)] via the intermolecular coupling of allene and allyldiphenylphosphine ligands. The intermediate complex [Ru(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)(MeCN){κ(<i>P</i>)-Ph<sub>2</sub>PCH<sub>2</sub>CHCH<sub>2</sub>}{η<sup>2</sup>-CH<sub>2</sub>CCMe<sub>2</sub>}][OTf] (<b>9</b>) has been spectroscopically characterized. The structure of complex [Ru(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>){κ(<i>P</i>),η<sup>4</sup>-Ph<sub>2</sub>PCH<sub>2</sub>CHCHC(Me)<sub>2</sub>CHCH<sub>2</sub>}][{3,5-(CF<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>}<sub>4</sub>B] (<b>6a</b>) has been resolved by X-ray diffraction analysis
