F. Bergamini et al., NOVEL PALLADIUM-CATALYZED CYCLODIMERIZATION OF BUTADIENE IN THE PRESENCE OF CARBON-DIOXIDE AND WATER, Journal of the Chemical Society, Chemical Communications, (9), 1995, pp. 931-932
The first example is reported of a palladium-catalysed cyclodimerizati
on of butadiene to 2-vinylmethylenecyclopentane occurring in catalytic
turnovers and yields far superior to the nickel-based systems, which
are claimed to be specific for cyclodimerization reactions.