Stereocontrolled monoalkylation of mixed-ring complex CpCp′ZrCl2 (Cp′ = 1-neomenthyl-4,5,6,7-tetrahydroindenyl) by lithium, magnesium and aluminum alkyls

Metal-Mediated and Metal-Catalyzed Reactions of Isocyanides

“…Dzhemilev and colleagues studied the CNCy insertion into the Zr–R bond of 174 that furnishes η 2 -iminoacyl complexes 175 (Alk = Et, 75%; Alk = Bu n , 79%) formed at the same diastereomeric ratio as in the starting zirconocene alkyl chlorides (toluene, RT, immediate reaction; Scheme ).…”

Mechanistic aspects of chemo- and regioselectivity in Cp2ZrCl2-catalyzed alkene cycloalumination by AlEt3

“…Energies of minima LM1 and LM2 are greater than that of zirconacyclopropane or styrene complexes LM3 and LM4. Probably, the dependence of catalytic alkene carbo-and cycloalumination enantioselectivity vs alkene structure [39] is the consequence of differences in the local minima stabilities as well.…”

Mechanism of Cp2ZrCl2-Catalyzed Olefin Cycloalumination with AlEt3: Quantum Chemical Approach

“…15 Moreover, the reaction of η 5 -cyclopentadienyl-η 5 -(1-neomenthyl-4,5,6,7-tetrahydroindenyl)zirconium dichloride (CpCp′ZrCl 2 ) with AlEt 3 under the same conditions yields two diastereomers of complex [CpCp′ZrEt(μ-Cl)•AlEt 3 ] (1a) in 1.6:1 ratio and then fivemembered bimetallic hydride complex [CpCp′Zr(μ-H)-CH 2 CH 2 AlEt 2 ] (3b) with 10:1 diastereomeric ratio. 16 Fivemembered hydride intermediates of this type were detected in the reaction of L 2 ZrCl 2 (L = CpMe, CpMe 5 , Ind) with AlEt 3 . 17 It was shown that the cyclic five-membered bimetallic Zr,Alcomplex 2 can act as the active intermediate of catalytic cycloalumination of terminal alkenes.…”

“…Experimental study of the cycloalumination reaction mechanism by NMR spectroscopy and X-ray diffraction analysis showed that the reaction of Cp 2 ZrCl 2 with AlEt 3 gives rise to a number of bimetallic complexes, including complexes 1 , 2 , and 4 (Scheme ). Moreover, the reaction of η 5 -cyclo­penta­dienyl-η 5 -(1-neomenthyl-4,5,6,7-tetra­hydro­indenyl)­zirconium dichloride (CpCp′­ZrCl 2 ) with AlEt 3 under the same conditions yields two diastereomers of complex [CpCp′­ZrEt­(μ-Cl)·AlEt 3 ] ( 1a ) in 1.6:1 ratio and then five-membered bimetallic hydride complex [CpCp′Zr­( μ- H)­CH 2 CH 2 ­AlEt 2 ] ( 3b ) with 10:1 diastereomeric ratio . Five-membered hydride intermediates of this type were detected in the reaction of L 2 ZrCl 2 (L = CpMe, CpMe 5 , Ind) with AlEt 3 .…”