A palladium-catalysed enolate alkylation cascade for the formation of adjacent quaternary and tertiary stereocentres

The catalytic enantioselective synthesis of densely functionalized organic molecules that contain all-carbon quaternary stereocentres is a challenge to modern chemical methodology. The catalytically controlled, asymmetric α-alkylation of ketones represents another difficult task and is of major interest to our and other research groups. We report here a palladium-catalysed enantioselective process that addresses both problems simultaneously and allows the installation of vicinal all-carbon quaternary and tertiary stereocentres at the α-carbon of a ketone in a single step. This multiple bond-forming process is carried out on readily available β-ketoester starting materials and proceeds by conjugate addition of a palladium enolate, generated in situ, to activated Michael acceptors. As a result, the CO_2 moiety of the substrate is displaced by a C–C fragment in an asymmetric cut-and-paste reaction with high yield, diastereomeric ratio and enantiomeric excess

Double Diffusive Magnetohydrodynamic (MHD) Mixed Convective Slip Flow along a Radiating Moving Vertical Flat Plate with Convective Boundary Condition

In this study combined heat and mass transfer by mixed convective flow along a moving vertical flat plate with hydrodynamic slip and thermal convective boundary condition is investigated. Using similarity variables, the governing nonlinear partial differential equations are converted into a system of coupled nonlinear ordinary differential equations. The transformed equations are then solved using a semi-numerical/analytical method called the differential transform method and results are compared with numerical results. Close agreement is found between the present method and the numerical method. Effects of the controlling parameters, including convective heat transfer, magnetic field, buoyancy ratio, hydrodynamic slip, mixed convective, Prandtl number and Schmidt number are investigated on the dimensionless velocity, temperature and concentration profiles. In addition effects of different parameters on the skin friction factor, [Formula: see text], local Nusselt number, [Formula: see text], and local Sherwood number [Formula: see text] are shown and explained through tables