A Novel C–N Migration Rearrangement Based on N–F Compounds for the Synthesis of N‐Alkyl Diaryl Ureas

Abstract

A novel rearrangement reaction based on the structure of N-fluoro-N-(phenylsulfonyl) benzamides (FPSBA) was developed. In the presence of base, unsymmetrical N-alkyl diaryl ureas were obtained in good yields which were accomplished through secondary alkyl phenylamines initiated 1,2-phenyl-shift migration rearrangement of N-fluoro-N-(phenylsulfonyl) benzamides. The reaction was carried out without using traditional, highly toxic reagents and noble metals. Whereas without rear- [a] Key .99. HRMS-EI (m/z) calcd. for (C 13 H 9 F 2 NO 3 S) 297.0271, found 297.0273. 2-Chloro-N-fluoro-N-(phenylsulfonyl)benzamide (1h):Following general procedure A, 1h was obtained in 89 % yield (274.2 mg, 1 mmol) as a white solid. -EI (m/z) calcd. for (C 13 H 9 FClNO 3 S) 312.9976, found 312.9978. 3-Chloro-N-fluoro-N-(phenylsulfonyl)benzamide (1i): Following general procedure A, 1i was obtained in 91 % yield (283.4 mg, 1 mmol) as a white solid. M.p.: 91.3-92.0°C. IR (KBr, cm -1 ): ν = 3089, δ = -49.54. HRMS-EI (m/z) calcd. for (C 13 H 9 FClNO 3 S) 312.9976, found 312.9973. 4-Chloro-N-fluoro-N-(phenylsulfonyl)benzamide (1j): Following general procedure A, 1j was obtained in 92 % yield (289 mg, 1 mmol) as a white solid. M.p.: 95.6-96.1°C. IR (KBr, cm -1 ): ν = 3093, δ = -49.99. HRMS-EI (m/z) calcd. for (C 13 H 9 FClNO 3 S) 312.9976, found 312.9978. 4-Bromo-N-fluoro-N-(phenylsulfonyl)benzamide (1k): Following general procedure A, 1k was obtained in 94 % yield (337 mg, 1 mmol) as a white solid. M.p.: 93.1-93.5°C. IR (KBr, cm -1 ): ν = 3100, δ = -49.97. HRMS-EI (m/z) calcd. for (C 13 H 9 FBrNO 3 S) 356.9471, found 356.9467. (1l): Following general procedure A, 1l was obtained in 98 % yield (316.2 mg, 1 mmol) as a yellow solid. M.p.: 130.5-131.2°C. IR (KBr, cm -1 ): ν = 3065, 2360, 1749, 1558, 1540, 1391, 1340. 1 H NMR (400 MHz, CDCl 3 ) δ = 8.39-8.32 (m, 2H), 8.06-8.02 (m, 2H), 7.89-7.85 (m, 2H), 7.84-7.78 (m, 1H), 7.68-7.61 (m, (C 13 H 9 N 2 O 5 S [M -F] -) 305.0232, found 305.0233. N-Fluoro-4-nitro-N-(phenylsulfonyl)benzamide Methyl 4-[Fluoro(phenylsulfonyl)carbamoyl]benzoate (1m):Following general procedure A, 1m was obtained in 99 % yield (333.7 mg, 1 mmol) as a white solid.

Bench‐Stable Electrophilic Fluorinating Reagents for Highly Selective Mono‐ and Difluorination of Silyl Enol Ethers

“…At the onset of our research, N ‐fluoro‐ N ‐(sulfonyl)amides 2 [26] were prepared as electrophilic reagents for selective monofluorination by reacting N ‐(sulfonyl)amide 1 or the corresponding lithium salt 1’ with N 2 ‐diluted F 2 (2 vol %) (Table 1). [17a] In the reaction of 1 , NaF (3 equiv) was added to trap in situ generated HF.…”