- Kinetic and mechanistic study on the thermal reactivity of stabilized phosphorus ylides, part 3: [(Acetyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and [(alkoxy-carbonyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and their thiocarbamoyl analogues
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A series of five [(acety])(arylcarbabmoyl)methylene]triphenyl-phosphoranes 1a-e and their thiocarbamoyl analogues 2a-e, |(alkoxycarbonyl)(arylcarbamoyl) methylene]triphenylphosphoranes 3a-e and thiocarbamoyl analogues 4a-e were prepared and fully characterized. All ylides are found under conditions of flash vacuum pyrolysis to fragment giving arylisocyanate or isothiocyanate and acetyl ylides or alkoxy ylides which undergo thermal extrusion of Ph3PO. A kinetic study shows that these reactions are unimolecular and are of first-order nature with no significant substituent effect. The thiocarbamoyl ylides 2 react from 4.6 to 42 times faster than their carbamoyl ylides 1, while the thiocarbamoyl ylides 4 react from 6.6 to 20.9 times faster than their carbamoyl ylides 3.
- Aitken, R. Alan,Al-Awadi, Nouria A.,Dawson, Graham,El-Dusouqui, Osman,Kaul, Kamini,Kumar, Ajith
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- RING TRANSFORMATIONS OF 3-PHENYL-4-TOSYLIMINO-1,3-THIAZETIDINE-2-ONE
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The title compound 1 can be transformed into functionalized 5- and 6-membered heterocycles by treatment with nucleophilic reagents.For instance, the reaction of 1 with tert-butyl isonitrile yields the two isomers 2 and 3, resulting from different positions of attack at the 4-membered ring.Diethylaminopropyne, on the contrary, reacts only at the C2-position of 1 giving rise to the 6-membered ring 4 in high yield.With phosphorus ylides, three pathways, all resulting from initial attack at the C2-atom of 1, have been observed depending on the substitution pattern of the ylide.
- L'abbe, Gerrit,Dekerk, Jean-Paul,Deketele, Martine
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p. 243 - 248
(2007/10/02)
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