Asymmetric synthesis of the F-pyran fragment of the altohyrtins

Article abstract of DOI:10.1016/S0040-4039(99)01481-1

The asymmetric synthesis of a differentially protected F-pyran ring of the altohyrtins has been achieved through an intramolecular cyclisation of a C₄₃ hydroxyl group onto a C₃₈-C₃₉ epoxide. Absolute stereochemistry was derived from an Evans boron aldol to control C₄₀ and C₄₁, the C₄₂-C₄₃ hydroxyl stereocentres from a Sharpless(-)-diethyl tartrate controlled epoxidation and the remaining stereocentres from substrate controlled diastereoselection.