A New Construct of the cis-3a-Aryloctahydroindole Skeleton via the [4+2] Cycloaddition of Furanyl Carbamates
摘要:
2-methylthio-5-amidofurans containing tethered unsaturation were prepared via the reaction of dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) with beta-alkoxy-gamma-dithiane amides. Thermolysis of these furans resulted in an intramolecular Diels-Alder reaction (IMDAF). The resulting oxa-bridged cycloadducts underwent a subsequent rearrangement to form bicyclic lactams. Model studies were directed toward mesembrine as well as the core skeleton of the 3,4-benzoerythrinane skeleton. Using this cascade sequence, a formal synthesis of the alkaloid erysotrine was accomplished.
Cyclizationcycloaddition cascades for the construction of azapolycyclic ring systems
作者:Albert Padwa、William S. Kissell、Cheryl K. Eidell
DOI:10.1139/cjc-79-11-1681
日期:——
reaction. An alternate route for the synthesis of cyclic amidofurans was developed using a Pummerer in- duced cyclization of the thiophenyl substituted acetal derived from the aldol reaction of methoxyphenylsulfanyl acetaldehyde with a-valerolactam. Treatment of the amido-substituted acetal with dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) generated an oxonium ion, which readily cyclized onto
A New Construct of the cis-3a-Aryloctahydroindole Skeleton via the [4+2] Cycloaddition of Furanyl Carbamates
作者:Albert Padwa、Cheryl K. Eidell、Stephen M. Lynch
DOI:10.3987/com-02-s(m)12
日期:——
2-methylthio-5-amidofurans containing tethered unsaturation were prepared via the reaction of dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) with beta-alkoxy-gamma-dithiane amides. Thermolysis of these furans resulted in an intramolecular Diels-Alder reaction (IMDAF). The resulting oxa-bridged cycloadducts underwent a subsequent rearrangement to form bicyclic lactams. Model studies were directed toward mesembrine as well as the core skeleton of the 3,4-benzoerythrinane skeleton. Using this cascade sequence, a formal synthesis of the alkaloid erysotrine was accomplished.