A novel amphiphilic chiral ligand derived from D-glucosamine. Application to palladium-catalyzed asymmetric allylic substitution reaction in an aqueous or an organic medium, allowing for catalyst recycling

A novel amphiphilic phosphinite-oxazoline chiral compound, 2-methyl-4,5-[4,6-O-benzylidene-3-O-bis{4-((diethylamino)methyl)phenyl}phosphino-1,2-dideoxy-alpha-D-glucopyranosyl]-[2,1-d]-2-oxazoline (1), has been prepared from natural D-glucosamine hydrochloride. The newly prepared complex, [Pd(2-methyl-4,5-[4,6-O-benzylidene-3-O-bis{(4-((diethylmethylammonium)methyl)phenyl)}phosphino-1,2-dideoxy-alpha-D-glucopyranosyl]-[2,-d]-2-oxazoline)(eta(3)-C3H5)](3+). 3BF(4)(-) (3), is soluble in water and an efficient catalyst for asymmetric allylic substitution reaction in water or an aqueous/organic biphasic medium (up to 85% eel. This catalytic system offers an easy separation of the aqueous catalyst phase from the product phase and allows recycling of the catalyst phase. In addition, compound 1 also works as an effective ligand for the palladium-catalyzed reaction under conventional homogeneous conditions in an organic medium, in which the catalyst (Pd-1 complex) can be recovered by simple acid/base extraction and reused in the second reaction.