Highly Active and Selective Platinum(II)-Catalyzed Isomerization of Allylbenzenes: Efficient Access to (E)-Anethole and Other Fragrances via Unusual Agostic Intermediates

Terminal alkene isomerization reactions are efficiently catalyzed by PtII complexes with E/Z selectivity as high as 98:2 and can be fruitfully applied to the preparation of some fragrances derived by isomerization of substituted allylbenzene derivatives. The involvement of agostic Pt···H intermediate species derived by insertion of the substrate into the Pt−aryl bond followed by β-hydride elimination is demonstrated, while kinetic studies and DFT calculations enable the formulation of a possible catalytic mechanism