Hydride transfer enabled switchable dearomatization of indoles in the carbocyclic ring and the pyrrole ring

Abstract

The hydride transfer enabled the first success of the regioselective dearomatization of indoles in the carbocyclic ring and the pyrrol ring, which was induced by ortho-quinone methides and vinylogous iminium...

Merging dearomatization with redox-neutral C(sp3)–H functionalization via hydride transfer/cyclization: recent advances and perspectives

“…In 2020, we collaborated with Xiao's group and reported the hydride transfer-enabled, regioselective dearomatization of indoles 68 in the carbocyclic ring and the pyrrole ring (Scheme 14). 19 To dearomatize the carbocyclic ring of indoles, an activating and directing hydroxy group was introduced to the carbocyclic ring of indole. In addition, screening of the reaction conditions showed that the addition of 5 Å molecular sieves and a ligand was essential for reaction efficiency.…”

“…9 Recently, a conceptually new hydride transfer-involved dearomatization, which combines two hot research fields of dearomatization and direct C(sp 3 )-H functionalization in a single reaction, has drawn much attention from chemists. [10][11][12][13][14][15][16][17][18][19] This "two-birds-with-one-stone" strat- egy opens a powerful avenue to not only streamline the synthesis of previously challenging target molecules but also prepare unreported structurally novel skeletons. In the past few years, with an ever-growing understanding of this rising area, our group have dedicated and made contributions to the hydride transfer-involved dearomatization reactions.…”

The Cascade [1,5]-Hydride Shift/Intramolecular C(sp3)–H Activation: A Powerful Approach to the Construction of Spiro-Tetrahydroquinoline Skeleton

“…Recently, Xiao’s group reported the first regioselective dearomatization between 4-hydroxindoles 43 or 4-hydroxycarbazole 45 and 2-aminobenzaldehydes 42 to construct spiro-tetrahydroquinolines via an aromatization-driven hydride shift strategy ( Scheme 6 ) ( Duan et al, 2020b ). Under the catalysis of scandium complex and HFIP, a variety of spirocyclic molecules incorporating indoles and carbazole moieties were provided with moderate to high yields, respectively.…”

Synergistic Sc(III)/Au(I)-Catalyzed Dearomative Spiroannulation of 2-(Ethynyl)aryl Cyclopropanes with 2-Aryl Indoles

“…2 Traditionally, there are three general approaches for the assembly of spiroindolenine skeletons, including intramolecular cyclization, 3 in situ [n + 2]-cycloaddition, 4 and direct spiroannulation (DSA). 5 Among these, the DSA strategy has attracted a lot of synthetic interest owing to the advantage of high efficiency and readily available feedstocks. 6 In general, this method usually relies on the sequential double alkylation reactions of indole derivatives with dielectrophiles.…”