Chlorocyanoketene (CCK), an exceptionally reactive electrophilic ketene, has previously been shown to undergo facile cycloadditions to imines,'formimidates, 2 aryl aldehyde~,~ s~ lfurdimides,~ and alkenes. 5 Its ability to cycloadd to selected alkynes is reported in this manuscript. Also reported is the observation that the resulting cyclobutenones function as precursors to vinylketenes. Indeed, the 4-chloro-4-cyanocyclobutenones arising from the ...
