Glycals were converted into thioethyl glycosyl donors through 1,2-anhydrosugar intermediates. Various participating groups in the C-2 position were examined for formation of -glucosyl, -galactosyl, and R-mannosyl linkages. A number of disaccharides was prepared employing a novel coupling protocol involving thioethyl 2-pivaloyl glycosyl donors and glycal acceptors. Using this methodology, a linear tetrasaccharide containing exclusively -glucosyl-(1f4) linkages was prepared in high yields. Ready application to R-mannosylation and C2 branching are other hallmarks of the method. Introduction and Purpose of the Investigation

The total synthesis of the title compound (1), starting with (R)-(−)-α-phellandrene (6), has been accomplished. The synthesis rigorously proves the relative stereochemical relationship of the diterpenoid and carbohydrate domains of eleutherobin. Key reactions included a Nozaki−Kishi ring closure to produce a furanophane (see 37 → 38), a pyranose to furanose transposition (see 50 → 47), and a novel oxycarbaglycosidation (cf. 58 → 87) for joining the two domains.

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