The reaction of the stabilisedylides 14–23 with an excess of NO2 in CH2Cl2 at room temperature gives different results depending on the structure of the starting ylide. The monacyl ylides 14–16 give the corresponding α-oxo nitriles 4 together with Ph3PO · HNO3 (24) which has been fully characterised for the first time. Under the same conditions, the ylide 18 gives 2,4-dinitrobenzonitrile (26), Ph3PO
Synthesis of 2-halo-2H-azirines from phosphorus ylides
作者:Teresa M.V.D. Pinho e Melo、António M.d'A. Rocha Gonsalves、Cláudia S.J. Lopes、Thomas L. Gilchrist
DOI:10.1016/s0040-4039(98)02413-7
日期:1999.1
α-Oxophosphonium ylides (3a–3e) react with N-chlorosuccinimide and N-bromosuccinimide in the presence of azidotrimethylsilane giving the corresponding haloazidoalkenes (4a–4g) with elimination of triphenylphosphine oxide. These compounds were completely converted to the 2H-azirines 5a–5g on heating in heptane.
Negatively substituted acetylenes. III. Reverse Wittig reactions with triphenylphosphine oxide and triphenylarsine oxide
作者:Engelbert Ciganek
DOI:10.1021/jo00831a001
日期:1970.6
Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 5. Selective extrusion of PH<sub>3</sub>PO from β,γ,β′-trioxo ylides to give diacylalkynes
作者:R. Alan Aitken、Hugues Hérion、Amaya Janosi、Nazira Karodia、Swati V. Raut、Shirley Seth、Ian J. Shannon、Fiona C. Smith
DOI:10.1039/p19940002467
日期:——
Sixteen examples of the previously unknown trioxo ylides 7 have been prepared by acylation of stabilised phosphorus ylides 8 with alpha-oxo acid chlorides 9. Extrusion of Ph(3)PO from these is readily achieved using FVP at 500 degrees C in most cases, to afford the diacylalkynes 10 in moderate yield. Three examples failed to give the expected alkynes and the nature of the processes involved in these cases is uncertain. Fully assigned C-13 NMR spectra are presented for the ylides and an unexpected pattern is observed in the value of J(p-c) for the three carbonyl carbons depending on the nature of the substituents present. There is some correlation between the value of (2)J(p-c) for the central carbonyl carbon and the success of the pyrolysis although this is not complete. The method has been used to prepare a specifically C-13 labelled acetylenic diester 14.
Gonsalves, Antonio M. d'A Rocha; Cabral, Ana M. T. D. P. V.; Melo, Teresa M. V. D. Pinho e, Synthesis, 1997, # 6, p. 673 - 676
作者:Gonsalves, Antonio M. d'A Rocha、Cabral, Ana M. T. D. P. V.、Melo, Teresa M. V. D. Pinho e、Gilchrist, Thomas L.