Total Synthesis of Tiacumicin B: Study of the Challenging β-Selective Glycosylations**

摘要: We give a full account of the total synthesis tiacumicin B (Tcn-B), natural glycosylated macrolide with remarkable antibiotic properties. Our strategy is based on our experience aglycone and unique 1,2-cis-glycosylation steps. used sulfoxide anomeric leaving-groups in combination remote 3-O-picoloyl group donors that allowed highly β-selective rhamnosylation noviosylation rely H-bond-mediated delivery. The rhamnosylated C1-C3 fragment was anchored to C4-C19 by Suzuki-Miyaura cross-coupling. Ring-size-selective Shiina macrolactonization provided semiglycosylated engaged directly noviolysation step virtually β-selectivity. Finally, novel deprotection method devised for removal 2-naphthylmethyl ether phenol, efficient all protecting groups synthetic tiacumicin B.