Double intramolecular oxymercuration: the first stereoselective synthesis of the C10–C34 fragment of asimitrin

The first stereoselective synthesis of the C10–C34 fragment of asimitrin, a nonclassical acetogenin, has been achieved. A key feature of our approach is the application of stereoselective double intramolecular oxymercuration for the efficient preparation of a mono-hydroxylated unsymmetrical bis-THF ring with two flanking hydroxyl groups. A chelation-controlled Grignard reaction plays a pivotal role in the elaboration of a commercially available carbohydrate.