Lithio-3-phenyl-1-propyne

However, treatment of cyclobutenone 1 with l-lithio-3-phenyl-1-propyne in THF at -78°C followed by addition of triethylamine (TEA) at room temperature, produces bicyclo[4.2.0]octadienyl-fused cyclobutenone 4 in 44% yield (Scheme 24.2). 

The reactivity of cyclobutenone 1 in the presence of l-lithio-3-phenyl-1-propyne is at first glance rather simple. A Michael-type addition of the anion to the conjugated ketone followed by elimination of lithium methoxide yields the addition compound 2 (Scheme 24.3). 

Treatment of 1 with l-lithio-3-phenyl-l-propyne in THF at -78°C, yields 3-alky-nyl eyelobutenone 2 that after being refluxed in toluene gives naphthofuran derivative 3 in 45% yield (Seheme 24.1). 

---