Rh(III)‐Catalyzed Csp²−Csp³ Bond Cleavage/Carbonylethylation of α‐Indolyl Alcohols

Abstract

A Rh(III)‐catalyzed Csp2−Csp3 bond cleavage/carbonylethylation of α‐indolyl alcohols with allylic alcohols has been reported. This transformation involved a cascade C−C bond cleavage/C−C bond formation, and provides a novel approach to assemble 2‐carbonylethylindole skeletons.

Mn(I)-Catalyzed Carbon-Skeleton Rearrangement of Tertiary Alcohol-Based Aldol Reaction with Aldehydes

“…Alcohols 1 – 2 ̃ 1 – 15 were prepared according to the literature procedures . Phenyl ketones (5.0 mmol) were dissolved in anhydrous THF (10 mL) in an oven-dried round-bottom flask under Ar environment.…”

“…An oven-dried Schlenk tube charged allylic alcohol 1 – 1 (0.10 mmol), 4-methylbenzaldehyde 2 – 1 (0.20 mmol, 2.0 equiv), Mn­(CO) 5 Br (0.02 mmol, 20 mol %), Me 2 Zn (0.10 mmol, 1.0 equiv), MgO (0.10 mmol, 1.0 equiv), ZnBr 2 (0.10 mmol, 1.0 equiv), and diglyme (0.1 mL) under an Ar atmosphere. The reaction mixture was then allowed to stir at 80 °C (heated by heating mantle) for 4 h. After the reaction mixture was cooled down, the reaction mixture was purified by flash chromatography on silica gel using ethyl acetate/petroleum ether (1:10) as eluent to afford the desired products 10 (49% yield) and 3 – 1 (23% yield).…”

“…Recently, Rh­(III)-catalyzed chelation-assisted cross-coupling reactions of secondary alcohols with carbenoids, alkylalcohols, and allylic alcohols via C–C σ bond activation were reported by us, in which a carbonyl moiety derived from C–C bond cleavage could not be efficiently reutilized. More recently, in order to reutilize the cut carbonyl moiety, we further developed Mn­(I)-catalyzed in situ group-inversion rearrangement of tertiary allylic alcohols via C–C σ bond activation; the mechanism studies confirmed that carbon-Mn σ bond protonation was involved in this carbon-skeleton rearrangement (Scheme , eq c) .…”

Rhodium(III)-Catalyzed Oxidative 1,3-Aryl Migration of α-Aryl Allylic Alcohols

“…3 Hz,1H),7.68 (d,J = 1.6 Hz,1H),3H),1H),1H), 4.09 (d, J = 1.9 Hz, 1H), 3.44 (d, J = 1.9 Hz, 1H), 2.17 (s, 3H); 13 C{ 1 H} NMR (126 MHz, CDCl 3 ): δ 203. 6, 141.2, 139.4, 130.4, 130.1, 129.2, 128.3, 125.8, 124.1, 107.3, 62.9, 55.8, 25 16 An oven-dried sealed tube charged 2a (0.20 mmol), [Cp*RhCl 2 ] 2 (5 mol %), Ag 2 CO 3 (109.6 mg, 0.40 mmol), and MeOH (2.0 mL) were added under air atmosphere. The reaction mixture was then allowed to stir at 85 °C for 24 h. After the reaction mixture was cooled down and filtrated, the corresponding filtrate was further concentrated under reduced pressure, followed by flash chromatography on silica gel using petroleum ether/ethyl acetate (4:1) as the eluent to afford the desired products 8.…”

Rhodium(III)-Catalyzed C–H Activation in Indole: A Comprehensive Report (2017–2022)

“…For example, treatment of 2-(1-hydroxybutyl)-1-DG-1H-indoles with but-3-en-2-ol gave 2-(3-oxobutyl)-1H-indoles that had further synthetic applications (Scheme 32). 73 The 2-(3-oxobutyl)-1H-indole was treated with ethyl carbonocyanidate followed by intramolecular cyclization using Pd(OAc) 2 to afford 4,5-dihydro-3aH-oxaz-olo [5,4-c]carbazol-2(6H)-one. The 2-(3-oxobutyl)-1H-indole reacts with a diazo compound Rh(II)-catalyzed coupling-cyclization to give 2,3,4,9-tetrahydro-1H-carbazoles.…”