Chemical-enzymatic synthesis of azasugar phosphonic acids as glycosyl phosphate surrogates

Starting from achiral materials two stereoisomeric phosphonylated dihydroxypyrrolidines containing four stereogenic centers were synthesized enantioselectively employing a combination of enzymatic and transition-metal-mediated methods. Both compounds contain features of the transition state of the enzyme-catalyzed fucosyl transfer reaction and represent building blocks of potential inhibitors against this class of enzymes.