Total Synthesis of (±)-Stenine Using the IMDAF Cycloaddition of a 2-Methylthio-5-amido-substituted Furan
作者:John D. Ginn、Albert Padwa
DOI:10.1021/ol025746b
日期:2002.5.1
[reaction: see text]. The intramolecular [4 + 2]-cycloaddition of a 2-methylthio-5-amidofuran was used to create the azepinoindole skeleton present in the Stemona alkaloid stenine. The rearranged cycloadduct was converted to stenine (1) in 11 additional steps via a sequence that features a Crabtree catalyst directed hydrogenation (9-->10), iodolactonization (2-->11), and a Keck allylation (11-->12)
Studies on the Synthesis of (±)-Stenine: A Combined Intramolecular [4 + 2]-Cycloaddition/Rearrangement Cascade
作者:Albert Padwa、John D. Ginn
DOI:10.1021/jo050515e
日期:2005.6.1
prepared via the reaction of dimethyl(methylthio)sulfonium tetrafluoroborate (DMSTF) with β-alkoxy-γ-dithiane lactams. Thermolysis of these furans resulted in an intramolecularDiels−Alderreaction (IMDAF). The resulting oxa-bridge cycloadducts underwent a subsequent 1,2-methylthio shift to form tricyclic lactams in high yield. Furan 9, annealed to an azepine ring, underwent the IMDAF reaction at or below