J. S. Yada6, Ch. Srini6as / Tetrahedron Letters 43 (2002) 3837–3839
3839
with (BOC)2O to give the cyclized product 15. The 2°
alcohol center of 15 was inverted after cleaving the
TBDMS ether by converting the resultant hydroxyl, via
its triflate, to the azide 16 with NaN3. Reduction of the
azide to the amine and simultaneous cleavage of the
benzyl ether was achieved in methanol with Pd/C under
a H2 atmosphere. The resultant crude aminol was cou-
pled with p-benzyloxybenzoyl chloride using triethyl-
amine in CH2Cl2 to give the Boc-protected hexa-
hydroazepine derivative 3.
Tadenborg, L.; Almario, A.; Pettersson, I.; Csoeregh, I.;
Kelly, N. M.; Andersson, P. G. Tetrahedron 1997, 53,
4857; (h) Miyabe, H.; Torieda, M.; Kiguchi, T.; Naito, T.
Synlett 1997, 580; (i) Miyabe, H.; Torieda, M.; Inoue, K.;
Tajiri, K.; Kiguchi, T.; Naito, T. J. Org. Chem. 1998, 63,
4397.
5. (a) Muller, A.; Takyar, D. K.; Wit, S.; Konig, W. A.
Liebigs Ann. Chem. 1993, 651; (b) Hughes, P. F.; Smith,
S. H.; Olson, J. T. J. Org. Chem. 1994, 59, 5799; (c) Hu,
H.; Jagdmann, G. E.; Hughes, P. F.; Nichols, J. B.
Tetrahedron Lett. 1995, 36, 3659; (d) Tuch, A. T.;
Saniere, M.; Le Merrer, Y.; Depezay, J. C. Tetrahedron:
Asymmetry 1996, 7, 2901; (e) Albertini, E.; Barco, A.;
Benetti, S.; De Risi, C.; Pollini, G. P.; Zanirato, V.
Tetrahedron 1997, 53, 17177; (f) Wu, M. H.; Jacobsen, E.
N. Tetrahedron Lett. 1997, 38, 1693; (g) Herdeis, C.;
Mohared, R. M.; Neder, R. B.; Schwabenlander, F.;
Telser, J. Tetrahedron: Asymmetry 1999, 10, 4521; (h)
Cook, G. R.; Shanker, P. S.; Peterson, S. L. Org. Lett.
1999, 1, 615; (i) Furstner, A.; Thiel, O. R. J. Org. Chem.
2000, 65, 1738; (j) Masse, C. E.; Morgan, A. J.; Panek, J.
S. Org. Lett. 2000, 2, 2571; (k) Ribber, D.; Hazell, R.;
Skrydstrup, T. J. Org. Chem. 2000, 65, 5382; (l) Genet, J.
P.; Phansavath, P.; Paule, S. D.; Vidal, V. R. Eur. J. Org.
Chem. 2000, 3903.
In summary, we have developed a simple, convenient
and efficient approach for the synthesis of the hexahy-
droazepine moiety of balanol involving a sequence of
reactions starting from (S)-2,3-O-isopropylidene glycer-
aldehyde. This approach offers high overall yield, use-
ful stereoselectivity, readily available starting materials
at low cost and simple experimental conditions which
make it a useful and attractive process for the total
synthesis of balanol. Further work is currently
underway.
Acknowledgements
6. Yadav, J. S.; Vidayanand, D.; Rajagopal, D. Tetrahedron
Lett. 1993, 34, 1191.
One of us (C.S.) thanks CSIR, New Delhi for financial
7. Rao, A. V. R.; Yadav, J. S.; Muralikrishna, V. Tetra-
hedron Lett. 1994, 35, 3613.
assistance.
8. Compound 4 was prepared by sodium periodate cleavage
of 1,2-O-isopropylidene-1,2,3,4-tetrol, which in turn was
prepared from ascorbic acid. See the following references
and references cited therein: (a) Jung, M. E.; Shaw, T. J.
J. Am. Chem. Soc. 1980, 102, 6304; (b) Abushnab, E.;
Venishetti, P.; Leiby, R. W.; Singh, H. K.; Mikkilineni,
A. B.; Wu, D. C.-J.; Saibaba, R.; Panzica, P. J. Org.
Chem. 1988, 53, 2598.
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9. Spectral data for selected compounds:
1
(a) Compound 8: H NMR (200 MHz, CDCl3, J in Hz,
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TMS internal standard) 1.6–1.8 (m, 4H), 3.47–3.80 (m,
6H), 4.6 (m, 2H), 7.25 (m, 5H); m/z (FAB) 240 (M+); IR
(neat/cm−1): 698, 749, 1071, 1454, 2928, 3406; [h]D=
−1.95 (c 1, CHCl3).
1
(b) Compound 9: H NMR (200 MHz, CDCl3, J in Hz,
TMS internal standard) 1.70–1.97 (m, 4H), 2.62–2.75 (m,
2H), 2.8 (d, 2H, J=5.9), 3.47–3.57 (m, 1H), 3.75 (s, 2H),
3.82–3.97 (m, 1H), 4.57 (d, 1H, J=11.9), 4.62 (d, 1H,
J=11.9), 7.25–7.42 (m, 10H); m/z (FAB) 312 (M+1); IR
(neat/cm−1): 699, 738, 1096, 1453, 2932, 3030, 3448;
[h]D=−7.09 (c 0.7, CHCl3).
1
(c) Compound 11: H NMR (300 MHz, CDCl3, J in Hz,
TMS internal standard) 1.6–1.85 (m, 4H), 2.65–2.75 (m,
2H), 2.85–2.9 (m, 1H), 3.22–3.3 (m, 1H), 3.35–3.45 (m,
2H), 3.8 (s, 3H), 4.4 (s, 2H), 4.45 (d, 1H, J=12), 4.62 (d,
1H, J=12), 6.82 (d, 2H, J=10.8), 7.2 (d, 2H, J=10.8),
7.27 (m, 5H); m/z (FAB) 342 (M+); IR (neat/cm−1) 699,
740, 821, 1034, 1094, 1247, 1456, 1512, 1612, 2859, 2928.
[h]D=+7.61 (c 1.5, CHCl3).
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