Total synthesis of woodrosin I -: Part 1:: Preparation of the building blocks and evaluation of the glycosylation strategy

The preparation of three building blocks required for the total synthesis of woodrosin 1 (1) is outlined, a complex resin glycoside bearing a macrolide ring which spans four of the five sugars of its oligosaccharide backbone. Key steps involve the enantioselective, titanium-catalyzed addition of dipentylzinc to 5-hexenal, the glycosylation of the resulting alcohol 18 with the glucose-derived trichloroacetimidate 7, and further elaboration of the resulting.