Methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD)

Abstract

Bulky designer aluminum Lewis acids of type 1 [1], first introduced into organic synthesis by Yamamoto and coworkers [2], provide remarkably versatile reagents for the control of regio-, stereo-and chemoselective transformations. The first described compound of this class, methylaluminum bis(2,6di-tert-butyl-4-methylphenoxide) (MAD) 1 proved to be a universal tool for the selective promotion of carbon-carbon bond formation, radical or pericyclic reactions. The reagent is readily available in a large scale from low cost commercial precursors [2].In general, use of MAD 1 gives good to excellent selectivities and yields but, if required, screening of related reagents like 5, 6 or even more bulky aluminium complexes with three phenolic substituents may result in improved results [4].