Studies on the BF3·Et2O catalyzed Baeyer–Villiger reaction of spiroketalic steroidal ketones
摘要:
During reactions of 23-oxosapogenins and the corresponding isomeric 22-oxo-23-spiroketals with MCPBA in the presence of BF3 center dot Et2O, equilibration occurs between the ketones. The Baeyer-Villiger type oxidation is followed by fragmentation to the dinorcholanic lactones and 3-methylbutyrolactone. The mechanistic aspects of these reactions in the 25R and 25S series are discussed. (C) 2010 Elsevier Inc. All rights reserved.