Gas-phase synthesis of N-alkenyl-3-hydroxypyrroles by sequential collapse of two dipolar intermediates
作者:Gordon A. Hunter、Hamish McNab
DOI:10.1039/c39930000794
日期:——
Flash vacuum pyrolysis (FVP) of the oxazolidinylmethylene derivatives of Meldrum's acid 1 and 2 gives alkenylpyrroles 5 and 6 respectively, by a mechanism which involves collapse of a bicyclic intermediate 3; FVP of the related compound 9(which cannot undergo this process) gives the tricyclic compound 11; probably via an intramolecular Diels–Alder reaction.
3-Hydroxypyrroles and 1H-pyrrol-3(2H)-ones. Part 14.1,2 Pyrolysis of oxazolidinylmethylene derivatives of Meldrum's acid – synthesis of N-alkenyl-3-hydroxypyrroles and related reactions
作者:Abd El-Aal M. Gaber、Gordon A. Hunter、Hamish McNab
DOI:10.1039/b109788a
日期:2002.2.6
Flash vacuum pyrolysis (FVP) of the title compounds 14 and 17 at 600–625 °C (0.005 Torr) gives the N-alkenylpyrrolones 22 and 23 respectively. The mechanism is shown to involve hydrogen transfer and cyclisation of the methyleneketene intermediate (e.g.25) to a fused pyrrolone (e.g.28). This species fragments to create an azomethine ylide which provides the alkenyl substituent by a further hydrogen