Answers are grounded in this paper and cite their sources.
Three's not a crowd: An intramolecular [2+2+2] cyclization between three different components, allene, alkyne, and alkene, has been realized using a catalytic amount of [Cp*RuCl(cod)] complex (cod = 1,5-cyclooctadiene), and afforded fused-tricyclic compounds in a highly stereoselective manner.
No takes yet. Share an insight, caveat, or question.
Saito et al. (2012) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: