Palladium(II)-Catalyzed Synthesis of α-Alkylidene-γ-butyrolactams from <i>N</i>-Allylic 2-Alkynamides. Total Synthesis of (±)-Isocynodine and (±)-Isocynometrine
作者:Xu Xie、Xiyan Lu、Yanyun Liu、Wei Xu
DOI:10.1021/jo001704u
日期:2001.10.1
actams via the Pd(II)-catalyzed cyclization of acyclic N-allylic 2-alkynamides via halopalladation, intramolecular olefin insertion, and beta-heteroatom elimination was developed. The reaction is less influenced by the leaving group and the concentration of the halide ions in comparison with the cyclization of acyclic alkynoates. The total syntheses of (+/-)-isocynodine and (+/-)-isocynometrine were
A new access to 3,5-disubstituted piperazinones via Pd(0)-catalyzed amination
作者:Benoit Ferber、Sébastien Lemaire、Mary M. Mader、Guillaume Prestat、Giovanni Poli
DOI:10.1016/s0040-4039(03)00885-2
日期:2003.5
An original synthetic route toward 3,5-disubstituted piperazinones has been developed. The method relies upon a 6-exo intramolecular process between a sulfonylated nitrogen atom of amino acid derivation and an eta(3)-allyl-palladium moiety. This cyclization process generates the two possible (cis and trans) diastereoisomers whose ratio depends on the amino acid employed. The bulkier the amino acid residue, the higher the observed cis:trans ratio. Convincing evidence for reversible intramolecular addition of the nitrogen nucleophile to the eta(3)-allyl-palladium complex is put forward. (C) 2003 Elsevier Science Ltd. All rights reserved.