10.1021/om100096g.s001 Doris Pun Doris Pun Emil Lobkovsky Emil Lobkovsky Ivan Keresztes Ivan Keresztes Paul J. Chirik Paul J. Chirik Cyclopentanone Insertion into η<sup>9</sup>-Indenyl Rings of Zirconium Sandwich Complexes American Chemical Society 2010 insertion 9H NMR spectroscopy equivalent compound indenyl Zirconium Sandwich ComplexesAddition diffraction ketone 2010-04-12 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Cyclopentanone_Insertion_into_sup_9_sup_Indenyl_Rings_of_Zirconium_Sandwich_Complexes/2778016 Addition of two equivalents of cyclopentanone to the bis(indenyl)zirconium sandwich compound (η<sup>9</sup>-C<sub>9</sub>H<sub>5</sub>-1,3-<sup>i</sup>Pr<sub>2</sub>)(η<sup>5</sup>-C<sub>9</sub>H<sub>5</sub>-1,3-<sup>i</sup>Pr<sub>2</sub>)Zr resulted in selective insertion of two equivalents of the ketone into the 1 and 4 positions of one of the indenyl ligands, and the resulting product was characterized by NMR spectroscopy and X-ray diffraction. For the mixed ring compound, (η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)(η<sup>9</sup>-C<sub>9</sub>H<sub>5</sub>-1,3-<sup>i</sup>Pr<sub>2</sub>)Zr, two isomeric double-insertion products were observed where C−C bond formation took place at the 1 and 4 (major) and 1 and 6 (minor) positions of the indenyl. The major product was characterized by X-ray diffraction. Deuterium labeling experiments and addition of substoichiometric amounts of ketones were used to gain insight into the preferred sites of insertion, and mono(ketone) intermediates were observed and characterized by NMR spectroscopy.