3234
M. C. Willis et al.
PAPER
N-(6-Benzyl-6-methylcyclohexen-1-yl)-tert-butylcarbamate
(Table 2, Entry 12)
References
(1) For examples, see: (a) Yet, L. Chem. Rev. 2003, 103, 4283.
(b) Davyt, D.; Entz, W.; Fernandez, R.; Mariezcurrena, R.;
Mombrú, A. W.; Saldaña, J.; Domínguez, L.; Coll, J.; Manta,
E. J. Nat. Prod. 1998, 61, 1560. (c) Toske, S. G.
Tetrahedron 1998, 54, 13459. (d) Kohno, J.; Koguchi, Y.;
Nishio, M.; Nakao, K.; Kuroda, M.; Shimizu, R.; Ohnuki, T.;
Komatsubara, S. J. Org. Chem. 2000, 65, 990.
Prepared using a modified version of the general procedure, using
6-benzyl-6-methylcyclohexen-1-yl triflate (174 mg, 0.5192 mmol),
ligand 4 (7.7 mg, 19.47 mmol) and Cs2CO3 as the base (237 mg,
0.7269 mmol), heating in dioxane (1.04 mL) at 100 °C for 17 h. The
product was isolated via flash column chromatography (1% Et2O–
PE) to yield the carbamate (118 mg, 75%); off-white solid; mp 64–
66 °C; Rf 0.17 (5% Et2O–PE).
(2) For examples see: (a) Fürstner, A.; Dierkes, T.; Thiel, O. R.;
Blanda, G. Chem. Eur. J. 2001, 7, 5286. (b) Gaulon, C.;
Dhal, R.; Chapin, T.; Maisonneuve, V.; Dujardin, G. J. Org.
Chem. 2004, 69, 4192. (c) Matsubara, R.; Nakamura, Y.;
Kobayashi, S. Angew. Chem. Int. Ed. 2004, 43, 1679.
(3) For reviews, see: (a) Ma, J.-A. Angew. Chem. Int. Ed. 2003,
42, 4290. (b) Tang, W.; Zhang, X. Chem. Rev. 2003, 103,
3029. (c) Blaser, H.-U.; Malan, C.; Pugin, B.; Spinder, F.;
Steiner, H.; Studer, M. Adv. Synth. Catal. 2003, 345, 103.
(4) Adam, W.; Bosio, S. G.; Turro, N. J. J. Org. Chem. 2004, 69,
1704.
(5) For some recent examples, see: (a) Gooßen, L. J.; Rauhaus,
J. E.; Deng, G. Angew. Chem. Int. Ed. 2005, 44, 4042.
(b) Brice, J. L.; Meerdink, J. E.; Stahl, S. S. Org. Lett. 2004,
6, 1845. (c) Harrison, P.; Meek, G. Tetrahedron Lett. 2004,
45, 9277. (d) Neugnot, B.; Cintrat, J.-C.; Rousseau, B.
Tetrahedron 2004, 60, 3575. (e) Burk, M. J.; Casy, G.;
Johnson, N. B. J. Org. Chem. 1998, 63, 6084.
IR (Nujol): 3400, 1737, 1706, 1514 cm–1.
1H NMR (CDCl3): d = 1.05 (s, 3 H, Me), 1.23–1.38 (m, 1 H), 1.46
(s, 9 H, Ot-Bu), 1.50–1.70 (m, 3 H), 2.05–2.15 (m, 2 H), 2.69 (d, J =
13.4 Hz, 1 H), 2.76 (d, J = 13.4 Hz, 1 H), 5.34–5.46 (br s, 1 H, NH),
6.00 (t, J = 4.0 Hz, 1 H), 7.13–7.18 (m, 2 H, ArH), 7.18–7.31 (m, 3
H, ArH).
13C NMR (CDCl3): d = 18.4, 24.8, 25.3, 28.3, 35.4, 37.8, 45.2, 79.5,
114.4, 126.2, 127.9, 130.4, 137.3, 138.1, 153.8.
CI–MS: m/z (%) = 302.3 (55) [M + H]+, 263.2 (15), 202.1 (90) [M
+ 2 H – CO2t-Bu]+, 112.1 (25).
HRMS (ES+): m/z calcd for C19H28NO2: 302.2115; found:
302.2114.
Coupling of 4-tert-Butylcyclohexen-1-yl Tosylate with
tert-Butylcarbamate (Table 2, Entry 13)
Prepared following the general procedure, using 4-tert-butylcyclo-
hexen-1-yl tosylate (160 mg, 0.5192 mmol), heating for 5 h. The
product was isolated via flash column chromatography (1% Et2O–
PE) to yield the carbamate (109 mg, 83%); viscous pale amber oil.
All the spectroscopic data were as above.
(6) For a recent review on the synthesis of enamines, enamides
and enol ethers using metal-mediated coupling reactions,
see: Dehli, J. R.; Legros, J.; Bolm, C. Chem. Commun. 2005,
973.
(7) (a) Kozawa, Y.; Mori, M. Tetrahedron Lett. 2002, 43, 111.
(b) Wallace, D. J.; Klauber, D. J.; Chen, C.-Y.; Volante, R.
P. Org. Lett. 2003, 5, 4759. (c) Klapers, A.; Campos, K. R.;
Chen, C.-Y.; Volante, R. P. Org. Lett. 2005, 7, 1185.
(8) (a) Ogawa, T.; Kiji, T.; Hayami, K.; Suzuki, H. Chem. Lett.
1991, 1443. (b) Shen, R.; Porco, J. A. Jr. Org. Lett. 2000, 2,
1333. (c) Wang, X.; Porco, J. A. Jr. J. Am. Chem. Soc. 2003,
125, 6040. (d) Han, C.; Shen, R.; Su, S.; Porco, J. A. Jr. Org.
Lett. 2004, 6, 27. (e) Fürstner, A.; Dierckes, T.; Thiel, O. R.;
Blanda, G. Chem. Eur. J. 2001, 7, 5286. (f) Nicolaou, K.
C.; Kim, D. W.; Baati, R. Angew. Chem. Int. Ed. 2002, 41,
3701. (g) Jiang, L.; Job, G. E.; Klapars, A.; Buchwald, S. L.
Org. Lett. 2003, 5, 3667. (h) Pan, X.; Cai, Q.; Ma, D. Org.
Lett. 2004, 6, 1809. (i) Coleman, R. S.; Liu, P. H. Org. Lett.
2004, 6, 577.
N-(3,4-Dihydronaphthalen-1-yl)-tert-butylcarbamate (Table 2,
Entry 14)
Prepared following the general procedure, using 1,2-dihydro-4-
naphthyl tosylate (156 mg, 0.5192 mmol), heating for 16 h. The
product was isolated via flash column chromatography (3% Et2O–
PE) to yield the carbamate (119 mg, 93%); pale yellow solid; mp
60.5–62.8 °C; Rf 0.19 (10% Et2O–PE).
IR (Nujol): 3315, 1740, 1699, 1527 cm–1.
1H NMR (CDCl3): d = 1.50 (s, 9 H, Ot-Bu), 2.30–2.39 (m, 2 H),
2.72–2.79 (m, 2 H), 5.95–6.08 (br s, 1 H, NH), 6.25–6.37 (m, 1 H,
C=CH), 7.13–7.23 (m, 4 H, ArH).
13C NMR (CDCl3): d = 22.1, 27.8, 28.3, 80.1, 115.9, 120.4, 126.4,
127.4, 127.8, 131.6, 131.8, 137.0, 153.9.
(9) For a review on the uses and preparations of triflate
CI–MS: m/z (%) = 246.2 (50) [M + H]+, 172.0 (100) [M – Ot-Bu]+,
derivatives, see: Ritter, K. Synthesis 1993, 735.
(10) Willis, M. C.; Brace, G. N. Tetrahedron Lett. 2002, 43,
9085.
146.0 (95) [M + 2 H – CO2t-Bu]+, 52.2 (50).
HRMS (ES+): m/z calcd for C15H20NO2: 246.1489; found:
246.1491.
(11) For reviews of Pd-catalysed aryl C–N coupling, see:
(a) Hartwig, J. F. In Handbook of Organopalladium
Chemistry for Organic Synthesis, Vol. 1; Negishi, E., Ed.;
Wiley-Interscience: New York, 2002. (b) Muci, A. R.;
Buchwald, S. L. Top. Curr. Chem. 2002, 219, 131.
(c) Prim, D.; Campagne, J.-M.; Joseph, D.; Andrioletti, B.
Tetrahedron 2002, 58, 2041.
(12) (a) Huang, X.; Anderson, K. W.; Zim, D.; Jiang, L.; Klapars,
A.; Buchwald, S. L. J. Am. Chem. Soc. 2003, 125, 6655.
(b) Huang, X.; Anderson, K. W.; Zim, D.; Jiang, L.; Klapars,
A.; Buchwald, S. L. J. Am. Chem. Soc. 2003, 125, 10767.
(13) Martinez, A. G.; Herrera, A.; Martinez, R.; Teso, E.; Garcia,
A.; Osio, J.; Pargada, L.; Unanue, R.; Subramanian, L. R.;
Hanack, M. J. Heterocycl. Chem. 1988, 25, 1237.
(14) McMurry, J. E.; Scott, W. J. Tetrahedron Lett. 1983, 24,
979.
Coupling of 4-tert-Butylcyclohexen-1-yl Tosylate with Morpho-
line (Table 2, Entry 15)
Prepared following the general procedure, using 4-tert-butylcyclo-
hexen-1-yl tosylate (160 mg, 0.5192 mmol) and morpholine (54
mg, 0.6.230 mmol) and a 5 mol% catalyst loading, heating for 36 h.
The product was isolated via Kugelrohr distillation (collecting be-
tween 105–120 °C/0.8 mmHg) to yield the enamine (63 mg, 54%)
as a white solid. All the spectroscopic data were as above.
Acknowledgment
This work was supported by the EPSRC and GlaxoSmithKline. The
EPSRC Mass Spectrometry Service at the University of Wales
Swansea is also thanked for their assistance.
(15) Comins, D. L.; Dehghani, A. Tetrahedron Lett. 1992, 33,
6299.
Synthesis 2005, No. 19, 3229–3234 © Thieme Stuttgart · New York