3-Alkenyl-2-silyloxyindoles in Vinylogous Mannich Reactions: Synthesis of Aminated Indole-Based Scaffolds and Products
摘要:
The first Lewis acid catalyzed vinylogous Mukaiyama-type Mannich addition of 3-alkenyl-2-silyloxyindoles to in situ generated N-Boc imines has been established, which affords chiral alpha-alkylidene-delta-amino-2-oxindole products with good efficiency and complete gamma-site- and Z-selectivity. The reaction is wide in scope, as it can be applied with equal convenience to different silyloxyindole donors and aromatic or aliphatic aminal-derived aldimine acceptors. The utility of these scaffolds is demonstrated by their easy transformation into either spirocyclopropane oxindole,, or homotryptamine-like products, featuring nontraditional indole-based skeleton connections.
Vinylogous Nucleophilic Substitution of the Hydroxy Group in Diarylmethanols with 3-Propenyl-2-silyloxyindoles: Towards the Synthesis of <i>α</i>
-Alkylidene-<i>δ</i>
-diaryl-2-oxindoles
作者:Amol P. Jadhav、Amjad Ali、Ravi P. Singh
DOI:10.1002/adsc.201601265
日期:2017.5.2
vinylogous substitution of the hydroxy group of diarylmethyl alcohols with 3‐alkenyl‐2‐silyloxyindoles, which affords broadly substituted α‐alkylidene‐δ‐diaryl‐2‐oxindole products with high efficiency and complete γ‐site and Z‐selectivity. The reaction displays very wide substrate scopes for both the reactants, benzhydryl alcohols and 3‐alkenyl‐2‐silyloxyindoles. The utility of the substituted adducts