Volpe, Emily C. Manke, David R. Bartholomew, Erika R. Wolczanski, Peter T. Lobkovsky, Emil B. Aryl−Oxazoline Chelates of First-Row Transition Metals: Structures of {κ-<i>C</i>,<i>N</i>-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub>(COCH<sub>2</sub>CMe<sub>2</sub>N)}FeCl(py) and [(κ-<i>C</i>,<i>N</i>-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub>(COCH<sub>2</sub>CMe<sub>2</sub>N)}Cr(μ-Cl)]<sub>2</sub> Aryl−oxazoline synthons have been explored for the preparation of strong-field first-row transition metal chelate species. With 4,4-dimethyl-2-phenyloxazoline (<b>HPhOx</b>), no CH bond activations afforded complexation, and aside from Zn(κ-<i>C</i>,<i>N</i>-4,4-Me<sub>2</sub>-2-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)oxazoline)<sub>2</sub> (<b>Zn(PhOx)</b><sub><b>2</b></sub>), aryl-coupling reactions were noted with 4,4-dimethyl-2-(2-lithiophenyl)oxazoline (<b>LiPhOx</b>) and MX<sub>2</sub>; [κ-<i>N</i>,<i>N</i>-{4,4-Me<sub>2</sub>-(2-<i>o</i>-C<sub>6</sub>H<sub>4</sub>)-2-oxazoline}<sub>2</sub>]CoCl<sub>2</sub> (<b>1</b>-Co) was structurally characterized. Metalations with 4,4-dimethyl-2-benzyloxazoline (<b>PhCH</b><sub><b>2</b></sub><b>Ox</b>) were prone to deprotonation, as exemplified by (Me<sub>2</sub>N)<sub>3</sub>Ti(η-<i>N</i>-(4,4-dimethyl-(2-CHPh)oxazoline)) (<b>2</b>) and bis-<i>N</i>,<i>N</i>′-(4,4-dimethyl-(2-pyridylmethylyl)oxazoline)Fe (<b>3</b>). Oxidative addition of 4,4-dimethyl-2-(2-bromophenylpropan-2-yl)oxazoline (<b>BrPhCMe</b><sub><b>2</b></sub><b>Ox</b>) to Ni(COD)<sub>2</sub> provided [{κ-<i>C</i>,<i>N</i>-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub>(COCH<sub>2</sub>CMe<sub>2</sub>N)}Ni]<sub>2</sub>(μ-Br)<sub>2</sub> (<b>4</b><sub><b>2</b></sub>). With 4,4-dimethyl-2-(2-lithiophenylpropan-2-yl)oxazoline (<b>LiPhCMe</b><sub><b>2</b></sub><b>Ox</b>), salt (FeBr<sub>2</sub>) metathesis proved uncompetitive with oxazoline ring-opening, as exhibited by [{κ-<i>N</i>,<i>O</i>-C<sub>6</sub>H<sub>4</sub>CMe<sub>2</sub>CNCMe<sub>2</sub>CH<sub>2</sub>(μ-O)-}BrFe{κ-<i>N</i>,<i>O</i>-C<sub>6</sub>H<sub>4</sub>CMe<sub>2</sub>CNCMe<sub>2</sub>CH<sub>2</sub>(μ-O)-}FeBr]Li {κ-<i>N</i>,<i>O</i>-C<sub>6</sub>H<sub>4</sub>CMe<sub>2</sub>-CNCMe<sub>2</sub>CH<sub>2</sub>(μ-O)-}(DME) (<b>5</b>-Fe<sub>2</sub>Li). Metatheses utilizing <b>(PhCMe</b><sub><b>2</b></sub><b>Ox)</b><sub><b>2</b></sub><b>Zn</b>, prepared from <b>LiPhCMe</b><sub><b>2</b></sub><b>Ox</b> and ZnCl<sub>2</sub>, gave structurally characterized dichromium, i.e., [{κ-<i>C</i>,<i>N</i>-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub> (COCH<sub>2</sub>CMe<sub>2</sub>N)}Cr]<sub>2</sub>(μ-Cl)<sub>2</sub> (<b>6</b><sub>2</sub>), and iron, i.e., {κ-<i>C</i>,<i>N</i>-{(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub>(COCH<sub>2</sub>CMe<sub>2</sub>N)}Fe(py)Cl (<b>7</b>) products. Bis-aryloxazoline metal complexes proved difficult to prepare, with {κ-<i>C</i>,<i>N</i>-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub>(COCH<sub>2</sub>CMe<sub>2</sub>N)}<sub>2</sub>M (M = Ni, <b>9</b>) the only clear example, although NMR evidence exists for M = Fe (<b>8</b>). PhCMe 2Ox;2N;LiPhCMe 2Ox salt;i.e;Zn;MX;Ni;dimethyl;LiPhCMe 2Ox;Fe;PhCH 2Ox;BrPhCMe 2Ox;CH bond activations;COCH;NMR evidence 2010-12-27
    https://acs.figshare.com/articles/dataset/Aryl_Oxazoline_Chelates_of_First_Row_Transition_Metals_Structures_of_i_C_i_i_N_i_i_o_i_C_sub_6_sub_H_sub_4_sub_CMe_sub_2_sub_COCH_sub_2_sub_CMe_sub_2_sub_N_FeCl_py_and_i_C_i_i_N_i_i_o_i_C_sub_6_sub_H_sub_4_sub_CMe_sub_2_sub_COCH_sub_2_sub_CMe_sub_2_sub_N_/2702509
10.1021/om100420z.s002