Phosphites and diamidophosphites based on mono-ethers of BINOL: a comparison of enantioselectivity in asymmetric catalytic reactions

Supported Ionic Liquid Phase (SILP) Allylic Alkylation of Amines in Continuous Flow

We present the use of Pd-complex-containing supported ionic liquid phases (SILPs) as a novel approach for continuous-flow allylic alkylation of N-nucleophiles. This immobilization strategy gave simple access to air-tolerating catalyst frameworks, providing rapid and convenient access to various achiral and chiral N-allylation products. Under optimized conditions, the flow-reaction could be maintained for 3.5 hours with constant product output; meanwhile, only a marginal 0.7 wt % of ionic liquid leaching and no detectable palladium-complex leaching could be observed.

Mechanistic insights into the tropo-inversion of the biphenyl moiety in chiral bis-amido phosphites and in their palladium(ii) complexes

Chiral bis-amido phosphites L1 and L2 containing a diaminobiphenyl unit and a chiral alkoxy group derived from either (-)-menthol or 3-acetoxy deoxycholic methyl ester have been synthesised. Both L1 and L2 react with PdCl₂(NCPh)₂ affording di- or mononuclear derivatives with formula trans-[Pd(μ-Cl)Cl(L)]₂ (1a, L = L1; 1b, L = L2) or trans-PdCl₂(L)₂ (2a, L = L1; 2b, L = L2) depending on the Pd : L molar ratio. The crystal structure of (M,P)-1a confirms the trans arrangement of the ligand L1 and shows an unusual puckering of the Pd₂(μ-Cl)₂ core (θ 46°). Both the ligands L1 and L2 and their complexes (1 and 2) are fluxional in solution as a consequence of the tropo-inversion of the diaminobiphenyl unit. For L1, L2, 1a and 2a a combined study including variable temperature ³¹P{¹H} NMR spectroscopy and line shape analysis, Eyring plots and DFT calculations have shed light on the mechanism of the tropo-inversion.