Synergistic‐Catalysis‐Enabled Reaction of 2‐Indolymethanols with Oxonium Ylides for the Construction of 3‐Indolyl‐3‐Alkoxy Oxindole Frameworks

Abstract

A synergistic-catalysis-enabled reaction of 2-indolymethanols with oxonium ylides has been established that makes use of a three-component reaction between 3-diazooxindoles, alcohols, and 2-indolymethanols under the cooperative catalysis of a metal complex and a Brønsted acid. This reaction has not only provided a new approach for the construction of 3-indolyl-3-alkoxy oxindole scaffolds by utilizing the C3-electrophilicity of an indole, but it is also the first example of a nucleophilic addition of a metal-associated ylide to 2-indolylmethanols. In addition, this reaction also includes a rarely reported trapping of onium ylides with aryl electrophiles.

N-Alkylation-Initiated Redox-Neutral [5 + 2] Annulation of 3-Alkylindoles with o-Aminobenzaldehydes: Access to Indole-1,2-Fused 1,4-Benzodiazepines

“…Indole-fused polycyclic architectures are attractive synthetic targets in the organic community and medical industry. , In particular, indole-1,2-fused 1,4-benzodiazepines and their derivatives, comprising privileged indole and benzodiazepine skeletons, have drawn tremendous attention as pharmaceutically important molecules (see Scheme a) . For instance, compound I has been identified as a type of antihypertensive .…”

Hydride Transfer Involved Redox-Neutral Cascade Cyclizations for Construction of Spirocyclic Bisoxindoles Featuring a [3,4]-Fused Oxindole Moiety

“…On the other hand, spirooxindoles represent one of the most attractive heterocyclic motifs which widely exist in alkaloids and pharmacologically interesting compounds such as cipargamin and satavaptan (Figure , IV – V ). , In recent decades, significant progress have been made for the synthesis of various functionalized spirooxindoles, owing to their diverse bioactivities and structural complexity. , Presumably, the combination of these two significant pharmaphores, i.e., [3,4]-fused oxindole and spirooxindole moieties, might produce a privileged structure possessing promising bioactivity. However, the synthesis of spirocyclic bisoxindoles featuring a [3,4]-fused oxindole moiety (Figure , VI ) poses a formidable challenge, and there has been no example available until now.…”

New Perspectives in the Indole Ring Functionalization using 2‐Indolylmethanols

“…The rhodium‐catalyzed reaction of 3‐diazooxindoles 51 with 2‐indolylmethanols 33 affords 3‐indolyl‐3‐ethoxyoxindoles 52 (Scheme ) . This approach is complementary to the direct aldol‐type reaction of indoles with isatins for the synthesis of these target compounds.…”