Full Paper
4:1, Rf = 0.25), ꢀ-lactams 16a and 16b (280 mg, 79 %) as an insepa-
rable mixture. It was determined that 17 mg of copper was used
during the reaction. The spectroscopic details of compounds 16a
and 16b were identical to those previously published.[2d]
126.25, 126.56, 126.63, 127.02, 127.09, 127.42, 128.36, 128.70,
134.42, 136.61, 137.96, 184.88 ppm.
1-Benzyl-3,3-dimethyl-1,3-dihydro-2H-benzo[g]indol-2-one
1
(18b): Discernible data: H NMR (500 MHz, CDCl3): δ = 1.54 (s, 6 H,
2 CH3), 5.50 (s, 2 H, NCH2Ph), 7.21–7.31 (m, 7 H, ArH), 7.41 (d, J =
8.0 Hz, 1 H, ArH), 7.60 (d, J = 8.0 Hz, 1 H, ArH), 7.79 (d, J = 8.0 Hz,
1 H, ArH), 8.00 (d, J = 8.0 Hz, 1 H, ArH), ppm. 13C NMR (125 MHz,
CDCl3): δ = 24.70, 43.97, 45.72, 120.04, 121.95, 123.56, 125.12,
125.79, 125.84, 127.25, 128.92, 129.21, 131.75, 134.29, 136.71,
137.24, 183.26 ppm.
Cyclisation of (E)-N-Benzyl-2-bromo-N-(2-methyl-but-1-enyl)-2-
methylpropionamide (17): Following the same procedure de-
scribed for the copper-catalysed ATRC cyclisation of 1, but at 45 °C
for 24 h, the reaction of compound 17 (650 mg, 2 mmol), TPMA
(6 mg, 0.02 mmol), Na2CO3 (11 mg, 0.1 mmol), and Cu wire (1 cm)
gave, after chromatography on silica gel (petroleum ether/EtOAc,
15:1, Rf = 0.25), ꢀ-lactams 17a/17b/17c (258 mg, 53 %) as an insep-
arable mixture. It was determined that 9 mg of copper was used
during the reaction. Data for the mixture: Rf = 0.32 (petroleum
Acknowledgments
ether/EtOAc, 4:1). IR (film): ν = 3030, 2968, 1751 cm–1. MS (ESI):
The authors thank the University of Warwick, UK for financial
support (grants to J. N. D. and J. R. D. H.).
˜
m/z = 298 [M + Na]+. HRMS (ESI): calcd. for C17H25NNaO2 [M + Na]+
298.1778; found 298.1776.
N-Benzyl-3,3-dimethyl-4-[(Z)-but-2-en-2-yl]azetidin-2-one
Keywords: Radical reactions · Redox chemistry · Cyclization ·
Copper · Homogeneous catalysis · Nitrogen heterocycles
1
(17a):[2d] Discernible data: H NMR (500 MHz, CDCl3): δ = 1.07 (s, 3
H, CH3), 1.29 (s, 3 H, CH3), 1.47 (d, J = 7.0 Hz, 3 H, CH3CH), 1.71 (s,
3 H, CH3), 3.80 (d, J = 15.0 Hz, 1 H, ArCHH), 3.92 (s, 1 H, 4-H), 4.83
(d, J = 5.0 Hz, 1 H, ArCHH), 5.54 (q, J = 7.0 Hz, 1 H, =CH), 7.21–7.34
(m, 5 H, ArH) ppm. 13C NMR (125 MHz, CDCl3): δ = 13.32, 14.71,
16.74, 22.95, 45.79, 54.85, 62.58, 124.49, 127.67, 128.46, 128.77,
130.76, 135.75, 174.56 ppm.
[1] a) L. J. Sebren, J. J. Devery III, C. R. J. Stephenson, ACS Catal. 2014, 4,
703–716; b) U. Jahn, Top. Curr. Chem. 2012, 320, 121–451; c) J. M. Muñoz-
Molina, T. R. Belderrain, P. J. Pérez, Eur. J. Inorg. Chem. 2011, 3155–3164;
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2006, 10, 217–224; g) A. J. Clark, Chem. Soc. Rev. 2002, 31, 1–11.
[2] For recent articles about the CuI-catalysed ATRC of N-allyl-α-haloamides,
see: a) A. A. Isse, G. Visonà, F. Ghelfi, F. Roncaglia, A. Gennaro, Adv. Synth.
Catal. 2015, 357, 782–792; b) A. J. Clark, A. Cornia, F. Felluga, A. Gennaro,
F. Ghelfi, A. A. Isse, C. Menziani, F. Muniz-Miranda, F. Roncaglia, D. Spinelli,
Eur. J. Org. Chem. 2014, 6734–6745; c) F. Bellesia, A. J. Clark, F. Felluga,
A. Gennaro, A. A. Isse, F. Roncaglia, F. Ghelfi, Adv. Synth. Catal. 2013, 355,
1649–1660; d) A. J. Clark, A. E. C. Collis, D. J. Fox, L. L. Halliwell, N. James,
R. K. O'Reilly, H. Parekh, A. Ross, A. B. Sellars, H. Willcock, P. Wilson, J. Org.
Chem. 2012, 77, 6778–6788; e) R. Casolari, F. Felluga, V. Frenna, F. Ghelfi,
U. M. Pagnoni, A. F. Parsons, D. Spinelli, Tetrahedron 2011, 67, 408–416;
f) A. J. Clark, P. Wilson, Tetrahedron Lett. 2008, 49, 4848–4850; g) M.
Bregoli, F. Felluga, V. Frenna, F. Ghelfi, U. M. Pagnoni, A. F. Parsons, G.
Petrillo, D. Spinelli, Synthesis 2011, 1267–1278; h) F. Ghelfi, M. Pattarozzi,
F. Roncaglia, V. Giangiordano, A. F. Parsons, Synth. Commun. 2010, 40,
1040–1051; i) M. Pattarozzi, F. Roncaglia, V. Giangiordano, P. Davoli, F.
Prati, F. Ghelfi, Synthesis 2010, 694–700; j) M. Pattarozzi, F. Roncaglia, L.
Accorsi, A. F. Parsons, F. Ghelfi, Tetrahedron 2010, 66, 1357–1364; k) Y.
Motoyama, K. Kamo, A. Yuasa, H. Nagashima, Chem. Commun. 2010, 46,
2256–2258.
N-Benzyl-3,3-dimethyl-4-[(E)-but-2-en-2-yl]azetidin-2-one
(17b):[2d] 1H NMR (500 MHz, CDCl3): δ = 1.04 (s, 3 H, CH3), 1.26 (s,
3 H, CH3), 1.49 (s, 3 H, CH3), 1.67 (d, J = 7.0 Hz, 3 H, CH3CH), 3.43 (s,
1 H, 4-H), 3.85 (d, J = 15.0 Hz, 1 H, ArCHH), 4.82 (d, J = 15.0 Hz, 1
H, ArCHH), 5.40 (q, J = 7.0 Hz, 1 H, =CH), 7.21–7.34 (m, 5 H, ArH)
ppm. 13C NMR (125 MHz, CDCl3): δ = 13.11, 14.73, 16.62, 22.35,
44.47, 54.85, 67.58, 121.10, 125.70, 128.40, 128.69, 130.76, 136.05,
174.41 ppm.
N-Benzyl-3,3-dimethyl-4-(but-1-en-2-yl)azetidin-2-one (17c): 1H
NMR (500 MHz, CDCl3): δ = 0.98 (t, J = 7.5 Hz, 3 H, CH2CH3), 1.05 (s,
3 H, CH3), 1.27 (s, 3 H, CH3), 1.85 (q, J = 7.5 Hz, 2 H, CH2CH3), 3.43
(s, 1 H, 4-H), 3.85 (d, J = 15.0 Hz, 1 H, ArCHH), 4.85 (d, J = 15.0 Hz,
1 H, ArCHH), 4.92 (s, 1 H, =CH), 5.08 (s, 1 H, =CH), 7.21–7.34 (m, 5
H, ArH) ppm. 13C NMR (125 MHz, CDCl3): δ = 11.83, 16.92, 22.20,
27.47, 44.09, 54.81, 65.48, 109.85, 127.65, 128.51, 128.74, 135.85,
145.65, 174.19 ppm.
Cyclisation of N-Benzyl-2-bromo-N-(3,4-dihydronaphthalen-1-
yl)-2-methylpropionamide (18): Following the same procedure
described for the copper-catalysed ATRC cyclisation of 1, but at
45 °C for 24 h, the reaction of compound 17 (650 mg, 2 mmol),
TPMA (6 mg, 0.02 mmol), Na2CO3 (11 mg, 0.1 mmol), and Cu wire
(1 cm) gave, after chromatography on silica gel (petroleum ether/
EtOAc, 10:1, Rf = 0.27), 18a and 18b (352 mg, 54 %) as an insepara-
ble mixture (18a/18b = 1.00:0.28). It was determined that 12.3 mg
of copper was used during the reaction. Data for the mixture: Rf =
[3] For recent articles about the RuII-catalysed ATRC of N-allyl-α-haloamides,
see: a) M. A. Fernández-Zúmel, G. Kiefer, K. Thommes, R. Scoppelliti, K.
Severin, Eur. J. Inorg. Chem. 2010, 3596–3601; b) K. Thommes, G. Kiefer,
R. Scopelliti, K. Severin, Angew. Chem. Int. Ed. 2009, 48, 8115–8119;
Angew. Chem. 2009, 121, 8259–8263; c) J. Wolf, K. Thommes, O. Briel, R.
Scopelliti, K. Severin, Organometallics 2008, 27, 4464–4474; d) K.
Thommes, B. Içli, R. Scopelliti, K. Severin, Chem. Eur. J. 2007, 13, 6899–
6907; e) N. Kanbayashi, K. Takenaka, T. Okamura, K. Onitsuka, Angew.
Chem. Int. Ed. 2013, 52, 4897–4901; Angew. Chem. 2013, 125, 4997–5001;
f) F. I. McGonagle, L. Brown, A. Cooke, A. Sutherland, Tetrahedron Lett.
2011, 52, 2330–2332; g) B. Dutta, R. Scoppelliti, K. Severin, Organometal-
lics 2008, 27, 423–429; h) C. D. Edlin, J. Faulkner, D. Fengas, M. Helliwell,
C. K. Knight, D. House, J. Parker, I. Preece, P. Quayle, J. Raftery, S. N.
Richards, J. Organomet. Chem. 2006, 691, 5375–5382; i) Y. Motoyama, S.
Hanada, N. Shimamoto, H. Nagashima, Tetrahedron 2006, 62, 2779–2788;
for the use of other redox complexes, see: j) M. Benedetti, L. Forti, F.
Ghelfi, U. M. Pagnoni, R. Ronzoni, Tetrahedron 1997, 53, 14031–14042; k)
Q. Liu, C. Chen, X. Tong, Tetrahedron Lett. 2015, 56, 4483–4485; l) C. K.
Tseng, E. G. Teach, R. W. Simons, Synth. Commun. 1984, 14, 1027–1031.
[4] For the preparation of ꢀ-lactams by ATRC, see: a) A. J. Clark, G. M. Battle,
Tetrahedron Lett. 2001, 42, 4409–4412; b) J. S. Bryans, N. E. A. Chessum,
A. F. Parsons, Tetrahedron Lett. 2001, 42, 2901–2905; while for the prepa-
0.32 (petroleum ether/EtOAc, 4:1). IR (film): ν = 3062, 3028, 2868,
˜
1679 cm–1. MS (ESI): m/z = 326 18a [M + Na]+, 324 18b [M + Na]+.
HRMS (ESI): calcd. for 18a C21H21NNaO [M + Na]+ 326.1515; found
326.1520. HRMS (ESI): calcd. for 18b C21H19NNaO [M + Na]+
324.1359; found 324.1364.
1-Benzyl-3,3-dimethyl-1,3,4,5-tetrahydrobenzo[g]indol-2-one
1
(18a):[2d] Discernible data: H NMR (500 MHz, CDCl3): δ = 1.32 (s, 6
H, 2 CH3), 2.29 (t, J = 8.0 Hz, 2 H, ArCH2CH2), 2.83 (t, J = 8.0 Hz, 2
H, ArCH2CH2), 5.06 (s, 2 H, NCH2Ph), 7.04 (t, J = 7.5 Hz, 1 H, ArH),
7.08 (t, J = 7.5 Hz, 1 H, ArH), 7.21–7.31 (m, 7 H, ArH) ppm. 13C NMR
(125 MHz, CDCl3): δ = 19.16, 22.46, 29.33, 45.43, 46.04, 121.54,
Eur. J. Org. Chem. 2016, 2479–2491
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