Formation of P-Ylide under Neutral and Metal-Free Conditions: Transformation of Aziridines and Epoxides to Conjugated Dienes In the Presence of Phosphine
作者:Ren-Hua Fan、Xue-Long Hou、Li-Xin Dai
DOI:10.1021/jo0354286
日期:2004.2.1
A general approach to formation of the P-ylide from the reaction of aziridines or epoxides with organophosphine under neutral and metal-free conditions is realized. Conjugated diene derivatives based on this kind of P-ylide were prepared in a facile and convenient way.
Comparison of the Catalytic Activity of [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Ru(2,2′-bipyridine)(L)]OTf versus [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Ru(6,6′-diamino-2,2′-bipyridine)(L)]OTf (L = labile ligand) in the Hydrogenation of Cyclohexanone. Evidence for the Presence of a Metal–Ligand Bifunctional Mechanism under Acidic Conditions
作者:Domenico DiMondo、Michelle E. Thibault、James Britten、Marcel Schlaf
DOI:10.1021/om400871v
日期:2013.11.11
The two title complexes as well as the dimeric complex [Ru(II)(eta(5)-C5H5)(6,6'-diamino-2,2'-bipyridine)12(OTf)(2) have been synthesized and characterized by NMR and single-crystal X-ray crystallography. The direct structural comparison of the 2,2'-bipyridine and 6,6'-diamino-2,2'-bipyridine complexes suggests that the electronic and steric environments of the ruthenium centers in both complexes are essentially equivalent, providing for a unique opportunity to probe the influence of the noncoordinated amine substituent on the relative reactivity and catalytic activity of the complexes. Opposite to what would be anticipated on the basis of steric effects, the bulkier amine-substituted ligand results in a catalyst showing substantially higher activity in the hydrogenation of cyclohexanone in acidic medium, which is attributed to the operation of a metal ligand bifunctional hydrogenation mechanism mediated by the amine substituents in their protonated form acting as proton shuttles.
Laber, Justus Liebigs Annalen der Chemie, 1954, vol. 588, p. 79,83