Chemoselective Removal of Allylic Protecting Groups Using Water-Soluble Pd(OAc)2/TPPTS Catalyst
The removal of allylic protecting groups promoted by the catalytic system Pd(OAc)(2)/TPPTS has been achieved on bifunctional substrates with complete chemoselectivity and high efficiency, in aqueous media. By lowering the amount of palladium catalyst, substituted allylic carboxylates remained unaffected while allylcarbamates, in the same molecule, were quantitatively removed. When using a biphasic C3H7CN-H2O solvent, the water-soluble catalyst could also differentiate allylcarbonates from dimethylallylcarbamates on diprotected amino alcohols. All these reactions were carried out under mild and neutral conditions which are compatible with a large range of molecules including beta-lactams.