Synthetic approaches to the manumycin A, B and C antibiotics: The first total synthesis of (+)-manumycin A

The first total synthesis of Manumycin A, as its (+)-enantiomer, is reported. The synthetic route features an asymmetric epoxidation (based on Wynberg's chiral phase transfer methodology) for the preparation of the key epoxyquinol nucleus, and a further demonstration of the utility of the Stille reaction for the construction of the Manumycin lower side chain. This synthesis of Manumycin A corrects the original stereochemical assignment and confirms the syn-hydroxy epoxide arrangement. The first syntheses of the quinones obtained by the oxidative degradation of Manumycins A-C are also described. (C) 1999 Elsevier Science Ltd. All rights reserved.