1474-24-4Relevant academic research and scientific papers
The value of 2JP–CO as a diagnostic parameter for the structure and thermal reactivity of carbonyl-stabilised phosphonium ylides
Aitken, R. Alan,Boubalouta, Youcef,Chang, Da,Cleghorn, Lee P.,Gray, Ian P.,Karodia, Nazira,Reid, Euan J.,Slawin, Alexandra M.Z.
, p. 6275 - 6285 (2017/09/29)
A survey of 20 carbonyl-stabilised phosphonium ylides with recently reported X-ray structures shows a strong correlation between the C[dbnd]P to C[dbnd]O torsion angle and the value of 2JP–CO, with high values being associated with an anti configuration and low with syn. Seven new X-ray structural determinations are reported, several for types of ylide not crystallographically characterised before, and these also conform to this pattern. The value of 2JP–CO is then correlated with whether or not thermal extrusion of Ph3PO occurs to give alkynes for over 200 ylides and an empirical rule developed that the extrusion never occurs for ylides where this value is > 11 Hz. This is used to rationalise the anomalous behaviour of some trioxo ylides and cyclic ylides, two of which afford cycloalkynes, isolated after rearrangement as the isomeric 1,3-dienes. The rule also holds for a family of novel highly fluorinated ylides which afford fluorinated alkynes in good yield upon flash vacuum pyrolysis.
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
