13162-69-1Relevant academic research and scientific papers
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
Aitken, R. Alan,Al-Awadi, Nouria A.,Dawson, Graham,El-Dusouqui, Osman,Kaul, Kamini,Kumar, Ajith
, p. 6 - 16 (2008/02/12)
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.
Reaction of Triphenylphosphine Radical Cation with 1,3-Dicarbonyl Compounds: Electrochemical One-Step Preparation of Dioxomethylenetriphenylphosphoranes
Ohmori, Hidenobu,Maeda, Hatsuo,Tamaoka, Mie,Masui, Masaichiro
, p. 613 - 620 (2007/10/02)
Electrochemical oxidation of Ph3P (1) in MeCN in the presence of 1,3-dicarbonyl compounds, R1COCH2COR2 (3), with HClO4 as the supporting electrolyte resulted in the formation of the phosphonium salts, Ph3P+ -CH(COR1)COR2 ClO4- (4), provided that R1 and/or R2 is a phenyl group.On the other hand, electrolysis in CH2Cl2 with 2,6-lutidinium perchlorate gave the phosphoranes, Ph3P=C(COR1)COR2 (5), directly from 1 and 3 in fair to excellent yields: in this case, R1 or R2 need not necessarily be a phenyl group.Thus, the electrolysis is shown to be a convenient method to prepare 5 in a single step.Plausible processes for the formation of 4 and 5 are proposed, involving the reaction of electrochemically generated Ph3P+. with the enol form of 3 as the keystep.Keywords - triphenylphosphine; 1,3-dicarbonyl compound; dioxomethyltriphenylphosphonium perchlorate; dioxomethylenetriphenylphosphorane; electrochemical oxidation; constant current electrolysis
Cumulated Ylides, XVI. A Method for the Exchange of the OH Group in Free Carboxylic Acids by the Ylide Function
Bestmann, Hans Juergen,Schade, Gerold,Schmid, Guenter,Moenius, Thomas
, p. 2635 - 2639 (2007/10/02)
Carboxylic acids 5 react with triphenylphosphorane (4) via the intermediate 6 with formation of the phosphoranes 7, which rearrange by heating in an intramolecular acyl migration to ylides 10.By heating of 10 in the presence of an alcohol 13 the acyl ylides 11 and urethanes 14 are formed.The reaction sequence allows the replacement of the OH group in carboxylic acids by the ylide function.
