Jl. Kent et al., A NEW ALLENIC PAUSON-KHAND CYCLOADDITION FOR THE PREPARATION OF ALPHA-METHYLENE CYCLOPENTENONES, Tetrahedron letters, 36(14), 1995, pp. 2407-2410
Alkynyl allenes undergo an intramolecular molybdenum-mediated Pauson-K
hand cycloaddition to provide functionalized alpha-methylene cyclopent
enones in one step.