Rhodium-Catalyzed Anti-Markovnikov Intermolecular Hydroalkoxylation of Terminal Acetylenes
摘要:
We report here the first transition-metal-catalyzed anti-Markovnikov intermolecular hydroalkoxylation of terminal acetylenes to give enol ethers in high yields without using bases. Arylacetylenes as well as alkenyl- and alkylacetylenes were coupled with aliphatic alcohols, and the products were obtained with high Z selectivity in most cases. Effective catalysts were 8-quinolinolato rhodium complexes, which are structurally simple but have been relatively unexplored as catalysts.
A nickel-catalyzed cross-coupling of alkenyl methyl ethers with Grignard reagents, undermildconditions, is described. These conditions allowed access to various stilbenes and heterocyclic stilbenic derivatives as well as to a potential anticancer agent DMU-212.
A transition-metal-free protocol for the synthesis of non-terminal alkenylethers, alkenylsulfides, and N-vinylazoles fromarylaldehydes or diarylketones, DMSO and O, S, N-nucleophiles has been reported. In this protocol, 24 examples of non-terminal alkenylethers and 28 examples of non-terminal alkenylsulfides in 72–95% yields have been synthesized within 5 min. Moreover, 27 examples of non-terminal