Tetrahedron

Prins-pinacol spiroannulations

KP Minor, LE Overman

Index: Minor, Keith P.; Overman, Larry E. Tetrahedron, 1997 , vol. 53, # 26 p. 8927 - 8940

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Citation Number: 34

Abstract

Lewis acid-promoted cyclizations of methylenecyclohexane siloxy acetals 14, 15, and 21 afford spiro [4.5] decanones 22, 25, and 29 in good yield. In all cases, exclusive pinacol rearrangement of C-1 of the original three-carbon acetal side chain is observed suggesting that pinacol rearrangement of the intermediate 9-decalyl cation occurs more rapidly than conformational equilibration. This selectivity should allow Prins-pinacol spiroannulations ...