Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 16. Model studies for the construction of conjugated polymers

Article abstract of DOI:10.1016/S0040-4020(99)00611-0

Reaction of a range of bis(ylides) with acid chlorides has been used to prepare the bis(oxoylides) 11-15. Similarly a range of simple ylides react with bis(acid chlorides) to give bis(oxoylides) 19-27 with the isomeric structure. Flash vacuum pyrolysis (FVP) of one example of the first type results in extrusion of Ph₃P rather than the expected Ph₃PO while six examples of the second type do extrude Ph₃PO upon FVP at 500 °C to afford the bis(alkynes) 28. Examples of the corresponding bis(tributylphosphonium ylides) have also been prepared but attempts to construct a tetrakis(oxoylide) 31 using a stepwise approach were unsuccessful. Fully assigned 13C NMR spectra are presented for six of the bis(oxoylides).