摘要:
The asymmetric synthesis of a differentially protected F-pyran ring of the altohyrtins has been achieved through an intramolecular cyclisation of a C-43 hydroxyl group onto a C-38-C-39 epoxide. Absolute stereochemistry was derived from an Evans boron aldol to control C-40 and C-41, the C-42-C-43 hydroxyl stereocentres from a Sharpless (-)-diethyl tartrate controlled epoxidation and the remaining stereocentres from substrate controlled diastereoselection. (C) 1999 Elsevier Science: Ltd. All rights reserved.