UNSYMMETRICAL BIARYL SYNTHESIS: AN APPROACH TO NATURAL HIGHLY FUNCTIONALISED BIARYLS VIA PALLADIUM CATALYSED COUPLING
The synthetic utility of the palladium catalysed cross-coupling reaction of aryl iodides and bromides with aryl Grignard reagents has been explored with respect to the polyoxygenated and polyalkylated arenes found in nature.High yields of unsymmetrical biaryls are obtained, free of symmetrical byproducts.The method will tolerate a limit of two ortho-substituents in the biaryl system with a preference for the 2 groups to be on the arylmagnesium ring.Transition state models of the potential rate determining steps are discussed with respect to this preference.