159051-97-5Relevant articles and documents
Flash Vacuum Pyrolysis of Stabilised Phosphorous Ylides. Part 6. Pyrolysis of Substituted Cinnamoyl Ylides as a Route to Conjugated Enynes
Aitken, R. Alan,Boeters, Christine,Morrison, John J.
, p. 2473 - 2480 (2007/10/02)
The substituted cinnamoyl ylides 6 and 7, readily prepared in one step from the quaternary phosphonium salts 8 and cinnamoyl chlorides 9, undergo extrusion of Ph3PO upon FVP to give the 1,3-enynes 12 and 13 in moderate yield.At 500 deg C there is little double bond isomerisation, but at 700 deg C this does occur to give almost 1:1 mixtures of E and Z isomers.In a few cases, including those with a nitrophenyl group present, the yields are poor or the reactions fail stabilised ylide was only partly successful since the severe conditions required for loss of the ester group resulted in significant isomerisation to naphthalene.The fully assigned 13C NMR spectra for 20 enynes are reported.One examples of the isomeric β,γ-unsaturated-δ-oxo ylides, 14 has been prepared and is found to undergo loss of Ph3P on FVP at 700 deg C to give indene and benzene in low yield.
