Preparation and nuclear magnetic resonance studies of diaryloxytriphenylphosphoranes. Correlation of substituent effects with 31P N.M.R. chemical shifts
Keyword(s):
Triphenylphosphine and diisopropyl azodicarboxylate react with phenols in tetrahydrofuran or chloroform at 0° to give diaryloxytriphenylphosphoranes. A linear free-energy relationship has been found between the 31P n.m.r. chemical shifts of many of these phosphoranes and the acid dissociation constants of the corresponding phenols. In general, electron-withdrawing groups on the phenol result in downfield 31P n.m.r. chemical shifts, while electron donating groups result in up-field shifts.
1971 ◽
Vol 93
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pp. 6984-6988
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2003 ◽
Vol 319
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pp. 179-194
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1977 ◽
Vol 32
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pp. 163-166
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1977 ◽
Vol 9
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pp. 533-535
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