The asymmetric catalytic synthesis of 3-cyclotryptamine substituted oxindoles through formal [4 + 2] cycloaddition/cyclization cascade is described. A wide range of cyclotryptamine derivatives were obtained in enantioenriched form under mild reaction conditions and were found to have potential anticancer activity. The strategy enables ready assembly of cyclotryptamine subunits at the C3a–C3a′ positions
描述了通过正式的[4 + 2]环加成/环化级联反应3-环色胺取代的羟吲哚的不对称催化合成。在温和的反应条件下,以对映体富集的形式获得了广泛的环色胺衍生物,发现它们具有潜在的抗癌活性。该策略使C 3a – C 3a'位置的环色胺亚基易于组装,并具有两个四级立体异构中心,具有顺式选择性,从而可以合成光学活性的顺式双(六氢吡咯并吲哚)和环色胺生物碱家族的其他化合物。
Regioselective Inter- and Intramolecular Formal [4+2] Cycloaddition of Cyclobutanones with Indoles and Total Synthesis of (±)-Aspidospermidine
way: A formal [4+2] cycloaddition between various cyclobutanones and indoles proceeded efficiently under Lewis acid catalysis (see scheme; PG = protecting group). The regioselectivity of the reaction could be controlled in such a way that each of the two possible regioisomers of a cycloaddition product could be synthesized selectively. The usefulness of this reaction for the total synthesis of hydrocarbazole
Catalytic Enantioselective Stereoablative Alkylation of 3-Halooxindoles: Facile Access to Oxindoles with C3 All-Carbon Quaternary Stereocenters
作者:Sandy Ma、Xiaoqing Han、Shyam Krishnan、Scott C. Virgil、Brian M. Stoltz
DOI:10.1002/anie.200902943
日期:2009.10.12
From 2 to 1! Racemic tertiary halooxindoles proceed to enantioenriched oxindoles bearing all‐carbon quaternarystereocenters as a result of a catalyticenantioselectivestereoablative process (see scheme). The application of this procedure allows for the rapid asymmetric construction of biologically significant alkaloid core motifs.
A new gold-catalyzed reaction of ynamides with 3-substituted indoles as nucleophiles is reported. The reaction allows for the synthesis of a new class of 2-vinylindole derivatives in good yields via the intermediacy of a cyclopropyl gold-carbenoid species.
The first total synthesis of racemic perophoramidine is described. The key step features the highly stereoselective introduction of the vicinial quaternary centers via base-promoted carbon-carbon bond formation between a 3-alkylindole and a 3-bromo-3-alkylindolin-2-one. This transformation presumably proceeds through a conjugate addition or Diels-Alder cycloaddition of the 3-alkylindole with a 3-alkylindol-2-one