Total synthesis of tricolorin A

摘要

Tricolorin A (1), a structurally amazing resin glycoside with promising bioactivities from ipomoea tricolor cav. (convolvulaceae), was synthesized in a total of 45 steps, with the longest linear sequence of 20 steps and overall yield of 0.65/100 from D-mannitol. The AB disaccharide 19-membrered lactone 2 was constructured by a regioselective macrolactonization using Corey-Nicolaou protocol. The macrolactone tetrasacchride 33 was realized either by "one-pot two-step" glycosylation procedure or by a stepwise assembly employing the "armed-disarmed" glycosylation strategy.