THE FLOW THERMOLYSES OF 1-ISOBUTENYL ALKYNYL- AND 2-METHYLPHENYL ALKYNYL KETONES. SYNTHESIS OF METHYLENOMYCIN B

Article abstract of DOI:10.1016/S0040-4039(00)83928-3

The gas flow thermolyses of 1-isobutenyl alkynyl and 2-methylphenyl alkynyl ketones were found to lead to phenols and to cyclopentenones.The results are explained by a 5-ring carbene process (the known α-alkynone cyclization) and a 6-ring as well as a 5-ring addition process.The latter two (novel) processes are thought to be intramolecular "C-H to C<*>C additions" in two directions.The 5-ring addition process was used in a short (but low yield) synthesis of methylenomycin B.