Approaches to the Cephalotaxine Skeleton Using an Intramolecular Heck Reaction.
作者:Masazumi IKEDA、Ken-ichi HIROSE、Serry A.A. EL BIALY、Tatsunori SATO、Takayuki YAKURA、Said M.M. BAYOMI
DOI:10.1248/cpb.46.1084
日期:——
1-[2-(o-Iodophenyl)acetyl]-2-(prop-2-enyl)-2-vinylpyrrolidine (17), upon treatment with palladium(II) acetate [Pd(OAc)2] in the presence of triphenylphosphine and triethylamine in refluxing acetonitrile, gave the monocyclization product 20 as the major product along with a small amount of the tandem cyclization product 21. On the other hand, treatment of the 1-[2-(o-iodophenyl)acetyl]-1-azaspiro[4.4]non-8-en-7-one (25) with Pd(OAc)2, 1, 3-bis-(diphenylphosphino)propane, tributylphosphine, and silver carbonate in boiling N, N-dimethylformamide afforded the cyclized product 27 in 51% yield.
1-[2-(邻碘苯基)乙酰基]-2-(丙-2-烯基)-2-乙烯基吡咯烷(17)在三苯基膦和三乙胺存在下于回流乙腈中用乙酸钯(II)[Pd(OAc)2]处理后,主要产物为单环化产物 20 和少量串联环化产物 21。另一方面,在沸腾的 N,N-二甲基甲酰胺中,用 Pd(OAc)2、1,3-双(二苯基膦)丙烷、三丁基膦和碳酸银处理 1-[2-(邻碘苯基)乙酰基]-1-氮杂螺[4.4]壬-8-烯-7-酮(25),可得到环化产物 27,收率为 51%。