Amino‐Directed Rh^III‐Catalyzed CH Activation Leading to One‐Pot Synthesis of NH Carbazoles

Abstract

One-pot synthesis: An efficient amino-directed one-pot synthesis of N-H carbazoles from unprotected 2-aminobiaryl compounds is reported. The free amino unit acts as both a directing group for ortho C-H activation and a functional group for construction of an N-heterocyclic ring (see scheme).

Direct Arylation-Based Synthesis of Carbazoles Using an Efficient Palladium Nanocatalyst under Microwave Irradiation

“…SiO2 (petroleum ether/EtOAc = 9:1). The spectral data were in accordance with those reported in the literature [13]. 1 3-methyl-9H-carbazole (6).…”

“…The spectral data were in accordance with those reported in the literature [19]. 1 3-Nitro-6-methoxy-9H-carbazole (13). The title compound was prepared from 3-methoxyaniline and 1,2-dichloro-4-nitrobenzene to give a yellow solid (0,15 g, 0.61 mmol, 61% yield).…”

Functional group directed C–H borylation

“…A second example of directed Rh-catalysed C-H borylation has been recently published, and it also involves a nitrogencontaining functionality as the directing group. In this case, Chen, Yan et al 34 LiAlH 4 in Et 2 O to afford the corresponding borohydride in 80% yield. Again, the formation of a borenium cation intermediate by attack of BBr 3 on the pyridine-BBr 3 adducts is proposed as the key step in the mechanism.…”

Ruthenium‐ and Rhodium‐Catalyzed Dehydrogenative ortho‐Alkenylation of Benzylamines via Free Amino Group Directed CH Bond Cleavage

“…Defying this conventional wisdom, we recently found that 2-aminobiphenyls undergo ruthenium-cata-lyzed direct coupling with alkynes accompanied by free amino group-directed C À H bond cleavage. [4][5][6] In the context of our further studies of ruthenium- [7,8] as well as rhodium-catalyzed [9,10] C À H functionalization, we succeeded in finding that a one-step synthesis of (isoindol-1-yl)acetate derivatives can be achieved by rhuthenium-or rhodium-catalyzed dehydrogenative coupling of N-unsubstituted a,a-disubstituted benzylamines with acrylates through free amino-directed ortho-alkenylation and successive domino cyclization. In addition, the direct coupling of the amines with styrenes could be conducted under rhodium catalysis.…”