Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-<i>b</i>]quinolines (quindolines)
作者:Michał Nowacki、Krzysztof Wojciechowski
DOI:10.3762/bjoc.14.14
日期:——
stabilized by alkoxycarbonyl, cyano or benzenesulfonyl groups react with nitroarenes to form σH-adducts, which in the presence of base (triethylamine or DBU) and trimethylchlorosilane transform into indolo[3,2-b]quinoline derivatives in moderate to good yields.
A general effective organocatalyzed synthesis of enantioenriched morphans with up to 92% ee was developed. The morphan scaffold was constructed in a one-pottandem asymmetric organocatalyzed Michaeladditionfollowed by a domino Robinson annulation/aza-Michael intramolecular reaction sequence from easily available starting materials.