Concluding Remarks and Perspectives of VDCPs
During the past years, the chemistry of VDCPs has rapidly developed. VDCPs, especially those with aromatic group(s) on the allene and/or cyclopropyl ring moiety, show diverse reaction patterns in the presence of Lewis acids, Brønsted acids, transition metal catalysts, etc. The chemistry of VDCPs greatly depends on the substituents on the allene and cyclopropyl ring moieties. Lewis or Brønsted acid-mediated chemistry of VDCPs has aroused a renaissance of cationic intermediates. Novel transformations of VDCPs developed during the past years have resulted in the synthesis of aromatic compounds, heterocyclic compounds, and some other useful products. It is believed that with continued investigations in this area, many new reactions and more useful chemistry of VDCPs will be found in the near future.