9
084
E. C. Gra6ett et al. / Tetrahedron Letters 42 (2001) 9081–9084
5. Stille, J. K. Angew. Chem., Int. Ed. Engl. 1986, 25,
solved in dry DMF (5 ml) under a N atmosphere. Some
2
5
08–524.
gentle warming was needed to aid dissolution. Finely
6
7
. Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457–2483.
. (a) Danieli, B.; Lesma, G.; Martinelli, M.; Passarella, D.;
Peretto, I.; Silvani, A. Tetrahedron 1998, 54, 14081–
crushed K PO (0.3 g, 1.4 mmol) was added to the DMF
3
4
solution and this slurry was heated to 60°C for 6 h. The
DMF was removed under reduced pressure to give a dark
solid which was initially purified by dissolving in DCM
and filtering through a plug of silica, followed by a
further elution of DCM (100 ml). The solvent was
removed under reduced pressure to give a brown crys-
talline solid that was further purified by flash column
chromatography with DCM as eluent to yield the cou-
pled product 13d (0.2 g, 0.41 mmol, 91%), mp 172–174°C.
1
4088; (b) Afarinkia, K.; Berna-Canovas, J. Tetrahedron
Lett. 2000, 41, 4955–4958.
. (a) Pirkle, W. H.; Dines, M. J. Org. Chem. 1969, 34,
8
9
2
239–2244; (b) Afarinkia, K.; Posner, G. H. Tetrahedron
Lett. 1992, 33, 7839–7842.
. Murata, M.; Oyama, T.; Watanabe, S.; Masuda, Y. J.
Org. Chem. 2000, 65, 164–168.
1
1
0. Oh-e, T.; Miyaura, N.; Suzuki, A. Synlett 1990, 221–223.
1. (a) Coudret, C.; Mazenc, V. Tetrahedron Lett. 1997, 38,
lH (CDCl , 300 MHz) 0.00 (6H, s), 0.87 (9H, s), 0.89
(3H, s), 0.96 (3H, s), 1.05–1.95 (19H), 2.18 (1H, m), 4.02
(1H, br. s), 5.85 (1H, m), 6.30 (1H, dd, J 9.6, 0.9), 7.42
3
5
293–5296; (b) Satoh, Y.; Gude, C.; Chan, K.; Firooznia,
F. Tetrahedron Lett. 1997, 38, 7645–7648.
(1H, dd, J 9.6, 2.4) and 7.48 (1H, br. s); lC (CDCl , 75
3
1
2. Typical procedure for the Suzuki couplings: The vinyl
MHz) −4.8, 16.4, 18.1, 21.1, 23.9, 25.9, 26.4, 26.8, 28.6,
29.9, 31.5, 34.2, 34.5, 35.2, 35.8, 36.6, 40.3, 47.4, 57.5,
67.3, 116.2, 116.4, 128.7, 144.3, 146.6, 147.1 and 161.5;
triflate of TBDMS protected 3b-etiocholanolone 12d
(0.24 g, 0.45 mmol), 2-pyrone-5-boronate 11 (0.14 g, 0.6
+
mmol), and PdCl (dppf) (40 mg, 0.045 mmol) were dis-
m/z (electrospray) 483 (MH ).
2