heated neat with methylcoumalate (la) at 165°C and the reaction product chrornatographed, the tosyl nicotinate (2a) was formed in 54% yield? Several other available pyrones were also subjected to these conditions at temperatures of 125180°C with mixed results as summarized in Table P . Trials with more stable6 activated nitrile dienophiles such as cyanofoxmates afforded no cycloaddition products even