Total synthesis of (+)-myriocin and (-)-sphingofungin E from aldohexoses using overman rearrangement as the key reaction

Total synthesis starting from aldohexoses of naturally occurring α-substituted α-amino acids, (+)-myriocin (1) and (-)-sphingofungin E (2), is described. Overman rearrangement of allylic trichloroacetimidate 6E derived from D-mannose effectively generated the tetrasubstituted carbon with nitrogen, and subsequent Wittig olefination afforded the highly functionalized moiety 3 of myriocin stereoselectively. Sulfone-mediated coupling reaction of the allyl bromide 3 with C₁₂ hydrophobic part 4 successfully constructed the carbon framework possessing E-olefin 28. Removal of the sulfone and protecting groups completed the chiral and stereoselective total synthesis of (+)-myriocin (1). A similar transformation starting from D-glucose also accomplished the total synthesis of (-)-sphingofungin E (2).