5-Methylene-2-cyclopentenones as new formal [2 + 2 + 1] cycloaddcts from[2-(dibenzylamino)ethenyl]carbenechromium complexes and alkynes
Abstract
2-Alylsubstituted pentacarbonyl {[2-(dibenzylamino]ethoxycarbene} chromium complexes 3a,b react with diphenylethyne 4, but 2-yne 5, or cyclooctne 6, to give 5-(dibenzylaminomethylene)-4-ethoxy-w-cyclopentenones 8a,b, 9a, 10a, and 10b in good yields (59–78%).