Synthesis of Diversely Functionalized Hexahydropyrrolo[2,3‐b]indoles Using Domino Reactions, Olefination, Isomerization and Claisen Rearrangement Followed by Reductive Cyclization.

Abstract

Fused pyrrole derivatives R 0160 Synthesis of Diversely Functionalized Hexahydropyrrolo[2,3-b]indoles Using Domino Reactions, Olefination, Isomerization and Claisen Rearrangement Followed by Reductive Cyclization. -A new and efficient route to biologically interesting pyrroloindoles is developed. -(KAWASAKI*, T.; OGAWA, A.; TERASHIMA, R.; SAHEKI, T.; BAN, N.; SEKIGUCHI, H.; SAKAGUCHI, K.-E.; SAKAMOTO, M.; J. Org. Chem. 70 (2005) 8, 2957-2966; Meiji Pharm. Univ., Kiyose, Tokyo 204, Japan; Eng.) -Jannicke 37-116

Anodic C(sp3)–H Acyloxylation of Indolin-3-ones Enabled by Oxidant-Free Cross-Dehydrogenative C(sp3)–O Coupling

“…To clarify the reaction mechanism in the anodic C(sp 3 )−H acyloxylation, the following control experiments were then conducted (Scheme 3). First, to verify whether the reaction occurred through the bromination process, 5,17 substrate 1 was electrolyzed for 1.0 h under acid-free reaction conditions. 1-Acetyl-2-hydroxyindolin-3-one (50) was found as the main byproduct and no bromine-containing intermediate was detected, probably due to the instability of the brominated intermediate, which was prone to further hydroxylation (eqn a).…”

“…Despite their biological importance, 3 the synthesis of indoline-like motifs with a C(sp 3 )−O bond at C2 positions is still rare. Some strategies have been implemented, including the oxidation of indole, 4 the bromination/nucleophilic reaction of indolin-3-ones with allyl alcohol, 5 and the hydroxylation of indolin-3-ones, 6 usually requiring a metal catalyst, Schmidt rearrangement conditions (NaN 3 /H 2 SO 4 ), or stoichiometric oxidants such as Br 2 , m-CPBA, or PhI(OAc) 2 . In addition, a metal-free strategy for direct C(sp 3 )−H acyloxylation of indolin-3-ones with carboxylic acid (3 equiv) by using 30% aq H 2 O 2 as a mild oxidant has also been realized, where the C2 positions of substrates need to be unsubstituted (Scheme 1a).…”

Spiro-3-indolin-2-ones: Synthesis, biological properties and computational studies

“…1,2 Synthesis of spiroheterocycles through the reactive carbonyl group is a subject of major interest for organic researchers. 3 Diverse synthetic methodologies have been reported for spiro-heterocycles, including intermolecular alkylation, 4,5 Morita-Baylis-Hillman, 6,7 1,3-dipolar cycloaddition, 8,9 Mannich/Pictet-Spengler, 3,10 sigmatropic rearrangement 11,12 and electrocyclization 13 reactions. Many natural spiro-indoles with considerable biological properties have been identified, of which maremycin G (isolated from Streptomyces sp.…”