- Intramolecular Cyclizations of Allenic Acylureas and -amides
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Allenic acids are found to add to dicyclohexylcarbodiimide affording, in the presence of Et2NH, the 4H-1,3-oxazin-4-ones 5 via 4.Under neutral conditions, they add to diaryl- or pyridyl(cyclohexyl)carbodiimides and triphenylketene imine to give the corresponding tricyclo(5.2.2.0 1,5)undeca-4,4,10-trien-3-ones 7,8,9, and 12.The allenic phenyl ester 13a dimerises, on heating in a (2+2) head-to-head fashion, to 14 but fails to undergo intramolecular Diels-Alder cyclization to 15.
- Trifonov, Latchezar S.,Oharovats, Alexander S.
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p. 262 - 270
(2007/10/02)
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- Cycloaddition of Carbodiimides and Triphenylketen-imine to Allenic Acids
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Allenic acids are found to add to dicyclohexylcarbodiimide affording, in the presence of secondary amines, the 1,3-oxazine-4-ones 5.Under neutral conditions, they add to diaryl- or aryl(cyclohexyl)carbodiimides and triphenylketen-imine to give the corresp
- Trifonov, Latchezar S.,Orahovats, Alexander S.
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p. 1585 - 1587
(2007/10/02)
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