Lewis acid-catalyzed [4 + 2] cycloaddition of 3-alkyl-2-vinylindoles with β,γ-unsaturated α-ketoesters

Further developments of β,γ-unsaturated α-ketoesters as versatile synthons in asymmetric catalysis

“…In addition, Zhang and Shi et al. described a Lewis acid-catalyzed [4 + 2] hetero-Diels–Alder reaction of 3-alkyl-2-vinylindoles with β,γ -unsaturated α -ketoesters recently ( Sun et al., 2022 ).…”

Domino Sonogashira coupling/metal carbene-involved annulation enabled by Pd/Cu relay catalysis: rapid assembly of indazole-containing biheteroaryls

“…Traditionally, metal-catalyzed carbon–carbon bond-forming reactions through merging two different heteroaromatic units are some of the most important methods for the synthesis of biheteroaryl systems. 3 These strategies mainly rely on pre-functionalized heteroaromatic substrates which are labile or difficult to synthesize in some cases, or even exhibit poor reactivity under conventional conditions. In addition, it is noteworthy that (multicomponent) domino annulative strategies have also attracted much attention because of their high efficiency and ready availability.…”

Lewis Acid‐Catalyzed (3+2) Cycloaddition of 2‐Indolylmethanols with β,γ‐Unsaturated α‐Ketoesters

“…[11] Therefore, developing C3-nucleophilic (3 + 2) cycloadditions of 2-indolylmethanols with two-carbon (2C) building blocks is highly desirable for constructing cyclopenta[b]indole skeletons. In this context, we wondered whether β,γ-unsaturated α-ketoesters [12][13][14][15][16][17][18] could serve as suitable 2C building blocks to undergo C3-nucleophilic (3 + 2) cycloadditions with 2-indolylmethanols. In recent years, β,γunsaturated α-ketoesters have been universally applied to (4 + n) cycloadditions as oxa-dienes (Scheme 2b).…”