An efficient Rh(III)-catalyzed coupling reaction of N-phenoxyacetamides with α,β-unsaturated aldehydes to give 1,2-oxazepines via C-H activation/[4+3] annulation has been developed. This transformation does not require oxidants and features C-C/C-N bond formation to yield seven-membered oxazepine rings at room temperature. Further derivation of 1,2-oxazepines leads to important chroman derivatives.

General Information1 H NMR, 13 C NMR spectra were recorded on a Bruker DPX-400 spectrometer with CDCl 3 as the solvent and TMS as an internal standard, operating at 400 MHz for 1 H NMR and 100 MHz for 13 C NMR. Melting points were measured by SGW X-4A microscopic apparatus. HRMS-ESI were measured by Q Exactive LC/HRMS spectrometer. Ethyl acetate and hexane were obtained from commercial sources and used for column chromatography without further purification. Other solvents were purified according to the standard methods. Other chemicals were obtained from commercial sources and used as received unless otherwise noted. All the anilides were synthesized through the coupling between corresponding aryl or alkyl acids and anilines according to previous procedures. 1 White solid, 64.0 mg, 72% yield, °C; 1 H NMR (400 MHz, CDCl 3 ): δ 2.14 (s, 3H), 2.18 (s, 3H), 6.79-6.84 (m, 2H), 7.21 (s, 1H), 7.54 (t, J = 7.54 Hz, 4H), 7.67 (t, J = 7.36 Hz, 2H), 7.92 (d, J = 7.92 Hz, 4H), 7.98 (d, J = 8.48 Hz, 1H); 13 C NMR (100 MHz, CDCl 3 ): δ 17. 63, 24.57, 122.40, 128.52, 129.06, 129.81, 130.09, 133.23, 133.53, 134.03, 137.86, 139.30, 168.52. HRMS-ESI(m/z): calcd for C 21 H 21 N 2 O 5 S 2 (M+H + ): 445.0886, found 445.0884. N-(2-methyl-4-(N-(phenylsulfonyl)phenylsulfonamido)phenyl)propionamide (3b)White solid, 65.0 mg, 71% yield, mp 185-186 °C; 1 H NMR (400 MHz, CDCl 3 ): δ 1.22 (t, J = 7.44 Hz, 3H), 2.14 (s, 3H), 2.41 (q, J = 7.39 Hz, 2H), 6.80 (d, J = 8.64 Hz, 1H), 6.84 (s, 1H), 7.22 (s, 1H), 7.54 (t, J = 7.58 Hz, 4H), 7.67 (t, J = 7.28 Hz, 2H), 7.91 (d, J = 8.. HRMS-ESI(m/z): calcd for C 22 H 23 N 2 O 5 S 2 (M+H + ): 459.1043, found 459.1045. N-(2-methyl-4-(N-(phenylsulfonyl)phenylsulfonamido)phenyl)isobutyramide (3c) White solid, 69.9 mg, 74% yield, mp 166-167 °C; 1 H NMR (400 MHz, CDCl 3 ): δ 1.25 (s, 3H), 1.27 (s, 3H), 2.18 (s, 3H), 2.53-2.61 (m, 1H), 6.81 (d, J = 8.72 Hz, 1H), 6.86 (s, 1H), 7.14 (s, 1H), 7.55 (t, J = 7.56 Hz, 4H), 7.65-7.70 (m, 2H), 7.93 (d, J = 7.96 Hz, 4H), 8.06 (d, J = 8.. HRMS-ESI(m/z): calcd for C 23 H 25 N 2 O 5 S 2 (M+H + ): 473.1199, found, 473.1195. N-(2-methyl-4-(N-(phenylsulfonyl)phenylsulfonamido)phenyl)cyclopropanecarboxamide(3d)White solid, 59.2 mg, 63% yield, mp 185-187 °C; 1 H NMR (400 MHz, CDCl 3 ): δ 0.86 (d, J = 4.92 Hz, 2H), 1.08 (s, 2H), 1.55-1.59 (m, 1H), 2.19 (s, 3H), 6.78 (d, J = 8.56 Hz, 1H), 6.85 (s, 1H), 7.35 (s, 1H), 7.54 (t, J = 7.54 Hz, 4H), 7.67 (t, J = 7.36 Hz, 2H), 7.97 (d, J = 7.88 Hz, 4H), 8.03 (s, 1H); 13 Light yellow solid, 68.4 mg, 64% yield, mp108-110 °C; 1 H NMR (500 MHz, CDCl 3 ): δ 1.97 (s, 3H), 2.68-2.75 (m, 2H), 3.07 (t, J = 7.35 Hz, 2H), 6.78-6.84 (m, 2H), 7.20-7.34 (m, 6H), 7.50-7.61 (m, 5H), 7.65-7.69 (m, 2H), 7.91-7.94 (m, 3H), 8.00 (d, J = 7.35 Hz, 1H); 13 (m/z): calcd for C 28 H 27 N 2 O 5 S 2 (M+H + ): 535.1356, found 535.1353. N-(2-methyl-4-(N-(phenylsulfonyl)phenylsulfonamido)phenyl)benzamide (3f) White solid, 67.8 mg, 67% yield, mp 167-169 °C; 1 H NMR (400 MHz, CDCl 3 ): δ 2.28 (s, 3H), 6.87 (d, J = 8.64 Hz, 1H), 6.91-6.96 (m, 1H), 7.48-7.51 (m, 2H), 7.5...

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Rhodium(III)-Catalyzed C-H Activation/[4 + 3] Annulation of N-Phenoxyacetamides and ,-Unsaturated Aldehydes: An Efficient Route to 1,2-Oxazepines at Room Temperature. -The Rh-catalyzed annulation of N-phenoxyacetamides (I) with ,-unsaturated aldehydes (II) leads to desired 1,2-oxazepines (III) in good to high yields. The reduction of oxazepine (IIIa) affords unexpected chroman (IV). The annulation of m-methoxy substrate (V) gives rise to a mixture of two isomeric 1,2-oxazepines (VI) and (VII). -(DUAN, P.; LAN, X.; CHEN, Y.; QIAN, S.-S.; LI, J. J.; LU, L.; LU, Y.; CHEN, B.; HONG, M.; ZHAO*, J.; Chem. Commun. (Cambridge) 50 (2014) 81, 12135-12138, http://dx.

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