Novel Formal Synthesis of Cephalotaxine via a Facile Friedel−Crafts Cyclization
作者:Wei-Dong Z. Li、Xin-Wei Wang
DOI:10.1021/ol070024b
日期:2007.3.1
[structure: see text]. A novel formal synthesis of cephalotaxine (CET), the parent structure of the antileukemia Cephalotaxus alkaloids, was achieved via a facile Friedel-Craftscyclization of the amino (or amido) spiro-cyclopentenone precursor (A) mediated by a protic acid leading to tetracyclic ketone B. A remarkable stereoelectronic effect of the methylenedioxy substituent (R) and an interesting
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.