Synthesis of a 10-membered ring with eleutheside functionality by Nozaki–Hiyama–Kishi coupling

The synthesis of a medium-sized unit of 15-seco-eleutheside analogue 3 has been achieved by the NiCl2/CrCl2-mediated intramolecular coupling of iodoaldehyde 8 with excellent yields. An important issue in our reported route to 3 involved a pyranose/furanose rearrangement, which opened the tetrahydrofuran ring on to the target.