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
Intramolecular [4+2]-cycloaddition reactions of cyclic 2-thiomethyl-5-amidofurans
作者:John D Ginn、Stephen M Lynch、Albert Padwa
DOI:10.1016/s0040-4039(00)01455-6
日期:2000.12
possessing tethered π-bonds were prepared by a dimethyl(methyl-thio) sulfonium tetrafluoroborate (DMTSF) induced cyclization of various amido dithioacetals. Upon heating, these systems undergo an intramolecular4+2-cycloaddition reaction. The initially formed Diels–Alder cycloadduct further rearranges by ring opening of the oxygen bridge followed by a subsequent 1,2-thiomethyl shift.