Pseudo allyl ligands

An X-ray structure determination was carried out on (C5Me5)RuBr2(Jt-C3H5), and showed a pseudo-piano-stool structure with two Br atoms and two terminal carbons for the endo-Jt-allyl ligand located at the basal positions. A crystal mirror plane bisects the pentamethylcyclopentadienyl and jt-allyl ligands. The oxidative addition of allylic halides to (C5R5)Ru(CO)2X is reversible, since the reductive elimination of... 

Enone formation-aromatization has been used for the synthesis of 7-hydro-xyalkavinone (716)[456]. The isotlavone 717 was prepared by the elimina-tion[457]. The unsaturated 5-keto allyl esters 718 and 719, obtained in two steps from myreene. were subjected to enone formation. The reaction can be carried out even at room temperature using dinitriles such as adiponitrile (720) or 1,6-dicyanohexane as a solvent and a weak ligand to give the pseudo-ionone isomers 721 and 722 without giving an allylated product(458]. 

Axial, equatorial Bonds or ligands of a cyclohexane (or saturated 6-membered heterocycle) chair conformation. The axial bonds are parallel to the C3 (Se) axis of cyclohexane (or the corresponding position of a heterocycle), and each equatorial bond is parallel to two of the ring bonds. In a cyclohexene, the corresponding allylic bonds or ligands are called pseudoaxial (ax ) and pseudo-equatorial (eq ). In a trigonal bipyramidal structure, the three ligands in a plane with the central atom are also known as equatorial. 

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