Synthesis of allenes via CuBr-catalyzed homologation of alk-1-ynes accelerated by microwave
作者:Hiroyuki Nakamura、Tsuyuka Sugiishi、Yuko Tanaka
DOI:10.1016/j.tetlet.2008.10.019
日期:2008.12
CuBr-catalyzed homologation of alk-1-ynes 1 with paraformaldehyde and N,N-diisopropylamine (or N,N-dicyclohexylamine) was accelerated by microwave irradiation at 150 °C to afford the corresponding allenes 2 in good to high yields in 1–10 min. Bisalkynes 5 and 7 were also converted to the corresponding bisallenes 6 and 8 in 63% and 61% yields, respectively, under the current condition.
The synthesis of regio- and stereoselective arylsubstitutedα,β-unsaturated aldehydes and ketones from activated allenes was achieved. This mild and non-metallic oxidation is exclusively driven by benign ambient air and triggered by visible light. The same starting materials under ideal anaerobic conditions led to the 2,3-diphenylselenation adduct with no trace of oxygenated products, demonstrating
Lewis Acid-Catalyzed Reaction of Allenes with Activated Ketone
作者:Min Shi、Bo Xu
DOI:10.1055/s-2003-41420
日期:——
Allenes react with activated ketone to give the corresponding addition products in good yields and good stereoselectivities in the presence of Lewis acid Yb(Otf)^3 and acetic anhydride or acetyl chloride as a quencher under mild reaction conditions.