Intermolecular hydroamination of methylenecyclopropane catalyzed by group IV metal complexes

TY - JOUR

T1 - Intermolecular hydroamination of methylenecyclopropane catalyzed by group IV metal complexes

AU - Smolensky, Elena

AU - Kapon, Moshe

AU - Eisen, Moris S.

PY - 2007/8/27

Y1 - 2007/8/27

N2 - The intermolecular hydroamination of methylenecyclopropane (MCP) and phenylmethylenecyclopropane (PhMCP) promoted by group IV metal complexes is presented. The reactivity and chemoselectivity of two titanium complexes having two different ancillary ligands, Ti(Ph2PNpy)2(NEt 2)2 and Ti(NMe2)4, are presented and compared to those of the zirconium complexes Zr(Ph2PNpy) 3NEt2 and Zr(NMe2)4. For the titanium complexes, the linear imine product A is always the predominant species, having E stereochemistry. For the zirconium complexes, the branched imine product B is obtained preferentially. Comparison of the activity of the complex Ti(Ph2PNpy)2(NEt2)2 with that of Ti(NMe2)4 reveals a strong relationship between the ancillary ligand at the catalytic complex and the suitability of the amine for the MCPs hydroamination reaction. A complex with a bulky ancillary ligand is suitable for the hydroamination of aliphatic amines and small aromatic amines, whereas a complex with a small ancillary ligand (steric hindrance) will allow the hydroamination of MCPs with bulky aromatic amines. Kinetic studies show that the hydroamination promoted by the homoleptic titanium complex exhibit a first-order dependence in complex and olefin and an inverse order dependence in amine. A plausible mechanism is presented on the basis of the obtained products, kinetic measurements, and syntheses of key intermediates.

AB - The intermolecular hydroamination of methylenecyclopropane (MCP) and phenylmethylenecyclopropane (PhMCP) promoted by group IV metal complexes is presented. The reactivity and chemoselectivity of two titanium complexes having two different ancillary ligands, Ti(Ph2PNpy)2(NEt 2)2 and Ti(NMe2)4, are presented and compared to those of the zirconium complexes Zr(Ph2PNpy) 3NEt2 and Zr(NMe2)4. For the titanium complexes, the linear imine product A is always the predominant species, having E stereochemistry. For the zirconium complexes, the branched imine product B is obtained preferentially. Comparison of the activity of the complex Ti(Ph2PNpy)2(NEt2)2 with that of Ti(NMe2)4 reveals a strong relationship between the ancillary ligand at the catalytic complex and the suitability of the amine for the MCPs hydroamination reaction. A complex with a bulky ancillary ligand is suitable for the hydroamination of aliphatic amines and small aromatic amines, whereas a complex with a small ancillary ligand (steric hindrance) will allow the hydroamination of MCPs with bulky aromatic amines. Kinetic studies show that the hydroamination promoted by the homoleptic titanium complex exhibit a first-order dependence in complex and olefin and an inverse order dependence in amine. A plausible mechanism is presented on the basis of the obtained products, kinetic measurements, and syntheses of key intermediates.

UR - http://www.scopus.com/inward/record.url?scp=34548583323&partnerID=8YFLogxK

U2 - 10.1021/om700455e

DO - 10.1021/om700455e

M3 - 文章

AN - SCOPUS:34548583323

SN - 0276-7333

VL - 26

SP - 4510

EP - 4527

JO - Organometallics

JF - Organometallics

IS - 18

ER -