Cp*Rh(iii) catalyzed ortho-halogenation of N-nitrosoanilines by solvent-controlled regioselective C–H functionalization

Abstract

We present a novel, efficient, and regioselective method for the rhodium-catalyzed direct C-H ortho-halogenation of anilines that involves a removable N-nitroso directing group. This method featured mild reaction conditions, wide substrate scope, good functional group tolerance and satisfactory yields. To maintain the high ortho-regioselectivity and conversion, increasing the steric hindrance of the solvent was critical. Preliminary mechanistic studies suggest that C-H activation may be involved in the rate-determining step.

Gold(I)-Catalyzed Cascade Cyclization of Anilines with Diynes: Controllable Formation of Eight-Membered Ring-Fused Indoles and Propellane-Type Indolines

“…According to the procedure described for the preparation of S2b , 4-chloro-2-iodoaniline ( S1c ) (991 mg, 3.91 mmol) was converted into S2c (271 mg, 26%) by the reaction with MeLi (1.16 M in Et 2 O; 4.05 mL, 4.69 mmol) and MeI (292 μL, 4.69 mmol) in THF (6.5 mL) at −78 °C to room temperature for 5 h. Column chromatography: silica gel (gradient 1 to 5% EtOAc in hexane); 1 H NMR (500 MHz, CDCl 3 ): δ 2.87 (d, J = 5.2 Hz, 3H), 4.15–4.24 (br m, 1H), 6.45 (d, J = 8.6 Hz, 1H), 7.20 (dd, J = 8.6, 2.3 Hz, 1H), 7.62 (d, J = 2.3 Hz, 1H). The 1 H NMR spectrum was in good agreement with that reported …”

“…The known compounds S1h , S1j , S2a , S2d , S2e , S2f , S2k , S3d , S4 , S5f , S5g , and S6 were synthesized according to the literature. The 1 H NMR spectra of S2c , S2g , and S5b were in good accordance with those reported in the literature. Structures of S1a , S1b , S1c , S1g , S1h , S1i , S1j , S2a – S2j , S3a – S3d , S4 , S5a – S5e , S6 , S7 , S8 are shown in Schemes S1–S5.…”

Rhodium(III)-Catalyzed Redox-Neutral [3+3] Annulation of N-nitrosoanilines with Cyclopropenones: A Traceless Approach to Quinolin-4(1H)-One Scaffolds

“…As shown In the past decade, transition-metal-catalyzed redox-neutral C-H activation reactions have emerged as a robust and versatile methodology, avoiding stoichiometric amounts of external oxidants [13][14][15]. Recently, N-nitroso [16][17][18] as a novel directing group has aroused increasing attention and has been successfully employed in transition-metal (e.g., Pd, Rh, etc.) catalyzed C-H functionalization (Scheme 1a) [19][20][21][22].…”

Recent Advances and Strategies for the Transition‐Metal‐Catalyzed C−H Functionalization of N‐Nitrosoanilines

“…Thus, 5 mol% [Cp*RhCl 2 ] 2 and 20 mol% AgSbF 6 in t BuOH at 30 °C were found to be the optimal reaction conditions (Scheme 25). [30] Extending the reaction with NIS resulted in excellent product yields. However, N ‐chlorosuccinimide (NCS) failed to give the expected chlorinated product.…”