Stereoselectivity Of D-Psicofuranosylation Influenced By Protecting Groups Of Psicofuranosyl Donors

Abstract – We synthesized several types of novel D-psicofuranosyl acetate derivatives, and investigated their use as glycosyl donors in scandium triflate-catalyzed D-psicofuranosylation reactions. Psicofuranosylation demonstrated unique stereoselectivities depending on the protecting groups of psicofuranosyl donors. The donor having a 3,4-isopropylidene group afforded β-psicofuranosides with high stereoselectivities. Donors having a C3 benzoyloxy group demonstrated low stereoselectivities with no neighboring group participation. This study also discusses the stereoselectivities of psicofuranosylation based on the conformers of the glycosyl oxocarbenium ion intermediates as influenced by the protecting groups of the psicofuranosyl donors. We also compared the neighboring group participation of the glycosyl donors bearing a C3 benzoyloxy group during D-psicofuranosylation and D-fructofuranosylation.