The Use of a Planar Chiral Ligand to Effect C−H Activation with Asymmetric Induction at an Iridium Center. Dramatically Different C−H Activation Stereoselectivities for Benzene and Cyclohexane

Half-sandwich iridium complexes—Synthesis and applications in catalysis

“…One enantiomer of the diiodide complex 131 was kinetically resolved with binaphthol to afford complex 134 with 100% diastereoselectivity. The iridium dihydride 133 has been found to be an excellent catalyst for stereoselective C-H bond activation of benzene and cyclohexane [79]. Complexes 131 and 133 Scheme 29.…”

Rhodium-Promoted Linear Tetramerization and Cyclization of 3,3-Dimethylbut-l-yne

“…Recently attention has focused on both linear oligomerization reactions [3±5] and on the trimerization of alkynes to form fulvenes, [6±8] potential synthons for substituted cyclopentadienyl ligands. [7,9] We had earlier found [6] that reaction of [Rh 2 (m-Cl) 2 (cod) 2 ] (cod cycloocta-1,5-diene) with tBuC 2 H and AgPF 6 in CH 2 Cl 2 led to the selective formation of the cationic fulvene complex 1 (Scheme 1), from which the free fulvene could be readily displaced by acetonitrile. In seeking to establish a catalytic version of this chemistry we added tBuC 2 H to a solution of the labile complex [Rh(NCMe) 2 (cod)][BF 4 ] [10] in dichloromethane, but were surprised to observe that there was no reaction at 40 8C.…”

Mono- and bis-[2-(P,P-dimethylphosphanyl)ethyl]tetramethylcyclopentadienyl zirconium(IV) complexes: Synthesis and structural studies in crystalline state and in solutions

“…The half-sandwich complexes [g 5 :g 1 -jP-C 5 H 4 CH 2 -CH 2 PMe 2 ]ZrCl 3 (4a) and [g 5 :g 1 -jP-C 5 Me 4 CH 2 CH 2 PMe 2 ]ZrCl 3 (4b) were prepared via corresponding ring-silylated cyclopentadienes 3a and 3b. The silanes 3a and 3b, in their turn, were synthesized from alkali metal salts 2a [2,11], 2b-Li or 2b-Na (prepared analogously to its Ph 2 P-counterpart [12]) (see Scheme 1).…”

“…Despite the compounds containing the dimethylphosphanyl moiety are somewhat synthetically ''inconvenient'' objects because of their extreme sensitivity to atmospheric oxygen, a representative series of side-chain Me 2 P-functionalized cyclopentadienyl ligands and metal complexes derived from them has been prepared and characterized [1][2][3][4][5][6][7][8][9][10]. Here we report the preparation of a new ring-permethylated cyclopentadienyl ligand C 5 Me 4 CH 2 CH 2 PMe 2 along with half-sandwich and sandwich Zr(IV) complexes derived from it.…”