443306-65-8Relevant academic research and scientific papers
Ruthenium-catalyzed aromatization of enediynes via highly regioselective nucleophilic additions on a π-alkyne functionality. A useful method for the synthesis of functionalized benzene derivatives
Odedra, Arjan,Wu, Chang-Jung,Pratap, Taduri Bhanu,Huang, Chun-Wei,Ran, Ying-Fen,Liu, Rai-Shung
, p. 3406 - 3412 (2005)
TpRu(PPh3)(CH3CN)2PF6 (10 mol %) catalyst effected the nucleophilic addition of water, alcohols, aniline, acetylacetone, pyrroles, and dimethyl malonate to unfunctionalized enediynes under suitable conditions (100 °C, 12-24 h) and gave functionalized benzene products in good yields. In this novel cyclization, nucleophiles very regioselectively attack the internal C1′ alkyne carbon of enediynes to give benzene derivatives as a single regioisomer. Experiments with methoxy substituents exclude the possible involvement of naphthyl cations as reaction intermediates in the cyclization of (o-ethynylphenyl) alkynes. Deuterium-labeling experiments indicate that the catalytically active species is ruthenium-π-alkyne rather than ruthenium-vinylidene species. This hypothesis is further confirmed by the aromatization of o-(2′-iodoethynyl)phenyl alkynes with alcohols. We propose a nucleophilic addition/insertion mechanism for this nucleophilic aromatization on the basis of a series of experiments.
