Regioselective spiroannulations of α??acetyl lactones

J Christoffers, H Oertling, W Frey

Index: Christoffers, Jens; Oertling, Heiko; Frey, Wolfgang European Journal of Organic Chemistry, 2003 , # 9 p. 1665 - 1671

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Citation Number: 3

Abstract

Abstract Monocyclic spiroannulation precursors 3a− c were obtained by Michael reactions of α-acetyl lactones 6a− c with methyl vinyl ketone (7). The selective formation of either regioisomer of both β-oxo (5a− c) and δ-oxo (4a− c) lactones from 3a− c was achieved by varying the reaction conditions. The δ-oxo lactones 4a− c were obtained under basic (buffered) conditions in a pyrrolidine/AcOH system. Under acidic conditions, the ...