ORGN 609 |
| The mechanism of acid-catalyzed dienone / phenol rearrangement involves two steps: the formation of carbocation intermediates, followed by the rate-limiting Wagner-Meerwein shift of an alkyl group, whose relative migratory aptitude determines the distribution of the regioisomeric phenol products. A mixture of regioisomers is usually formed in the absence of significant difference in migratory aptitudes for the alkyl group. In this study we present a mild ZnCl2- mediated rearrangements of monosilylated-1, 4-dihydronaphthalenediol, which gives a single regioisomer confirmed by NMR NOE experiment. The alkyl group that migrates is determined not by its relative migratory aptitude but by its positioning next to the protected hydroxy group. The current method provides a general regiospecific preparation for predetermined 2,4-disubstituted-1-naphth-ols.
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Asymmetric Reactions, Heterocycles, Aromatics, Combinatorial, and Physical Organic Chemistry
8:00 PM-10:00 PM, Wednesday, 31 August 2005 Washington DC Convention Center -- Hall A, Poster
Division of Organic Chemistry |
