C O M M U N I C A T I O N S
Table 2. Mn(III)-Catalyzed Synthesis of
References
2-Azabicyclo[3.3.1]non-2-en-1-ols 6a b
,
(1) For recent reviews, see:(a) Progress in Heterocyclic Chemistry; Gribble,
G. W., Joule, J. A., Eds.; Elsevier: Oxford, 2008; Vol. 20 and others in
this series. (b) ComprehensiVe Heterocyclic Chemistry III; Katritzky, A. R.,
Ramsden, C. A., Scriven, E. F. V., Taylor, R. J. K., Eds.; Pergamon: Oxford,
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2008, 10, 313.
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62, 5864. (b) Bamford, A. F.; Cook, M. D.; Roberts, B. P. Tetrahedron
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Stella, L. In Radicals in Organic Synthesis; Renaud, P., Sibi, M. P., Eds.;
Wiley-VCH: Weinheim, 2001; Vol. 2, p 407. (b) Mikami, T.; Narasaka,
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(5) For reports on the oxidative generation of ꢀ-carbonyl radicals from
cyclopropanol derivatives and their addition to alkenes, see:(a) Hasewawa,
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a Unless otherwise noted, the reactions were carried out by addition
of a solution of cyclopropanols 5 (1.2 equiv) in MeOH via a syringe
pump over 1 h to a solution of vinyl azides 1 (0.3 mmol) and Mn(acac)3
(10 mol %) under N2 atmosphere at room temperature (see Supporting
Information). b Isolated yield was noted above. c 20 mol % of Mn(acac)3
was used. d 40 mol % of Mn(acac)3 was used. e Vinyl azide 1h was
f
1
recovered in 68% yield. The ratio was determined by H NMR, and the
major exoisomer was shown above.
Scheme 4. Transformations of 2-Azabicyclo[3.3.1]non-2-en-1-ol
6aaa
(6) For recent reviews on synthesis of pyridines, see:(a) Bagley, M. C.; Glover,
C.; Merritt, E. A. Synlett 2007, 2459. (b) Heller, B.; Hapke, M. Chem.
Soc. ReV. 2007, 36, 1085. (c) Ciufolini, M. A.; Chan, B. K. Heterocycles
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(7) For recent selected reports on synthesis of pyridines, see:(a) Manning, J. R.;
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Soc. 2005, 127, 7774. (l) McCormick, M. M.; Duong, H. A.; Zuo, G.; Louie,
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a Reagents and conditions: (a) Ac2O (8.0 equiv), Et3N (2.0 equiv), DMAP
(0.1 equiv), CH2Cl2, rt,
3 h, 86%; (b) NaBH(OAc)3 (3.0 equiv),
AcOHsCH2Cl2 (1:2), 5 h, 76%; (c) TiCl4 (1.5 equiv), Et3SiH (2.0 equiv),
CH2Cl2, rt, 3 h, 90%; (d) Me3Al (4.0 equiv), CHCl3, rt, 1 h, 83%; (e) TiCl4
(1.5 equiv), CH2dCHCH2SiMe3 (2.0 equiv), CH2Cl2, rt, 3 h, then 1 N HCl,
THF, 0.5 h, 82%
(8) For more details of screening of the reaction conditions, see Supporting
Information.
(9) Figgis, B. N.; Raston, C. L.; Sharma, R. P.; White, A. H. Aust. J. Chem.
1978, 31, 2545.
azabicyclo[3.3.1]nonane or -non-2-ene frameworks were ex-
ploited. Further investigation of the scope and synthetic ap-
plication of these reactions are currently underway and will be
reported in due course.
(10) A proposed reaction mechanism on the formation of dihydropyrroles 4 was
discussed in the Supporting Information.
(11) The structures of 4an, 6aa, 6ha, 6ab, 6ac, and 8 were determined by X-ray
crystallographic analyses; see Supporting Information.
(12) For recent synthetic reports, see:(a) Ieda, S.; Asoh, Y.; Fujimoto, T.; Kitaoka,
H.; Kan, T.; Fukuyama, T. Heterocycles 2009, 79, 721. (b) Patir, S.; Uludag,
N. Tetrahedron 2009, 65, 115. (c) Aurrecoechea, J. M.; Gorgojo, J. M.;
Saornil, C. J. Org. Chem. 2005, 70, 9640. (d) Sole´, D.; Peidro´, E.; Bonjoch,
J. Org. Lett. 2000, 2, 2225. (f) Quirante, J.; Escolano, C.; Merino, A.;
Bonjoch, J. J. Org. Chem. 1998, 63, 968.
(13) For recent selected reports, see:(a) Thomas, J. B.; Zhang, L.; Navarro, H. A.;
Carroll, F. I. J. Med. Chem. 2006, 49, 5597. (c) Kim, I. J.; Dersch, C. M.;
Rothman, R. B.; Jacobson, A. E.; Rice, K. C. Bioorg. Med. Chem. 2004,
12, 4543.
Acknowledgment. This work was supported by funding from
Nanyang Technological University, Singapore Ministry of Educa-
tion, and Science & Engineering Research Council (A*STAR Grant
No. 082 101 0019). We thank Dr. Yongxin Li (Division of
Chemistry and Biological Chemistry, School of Physical and
Mathematical Sciences, Nanyang Technological University) for
assistance in X-ray crystallographic analysis.
(14) For a report on C-C bond formation at bridgehead iminium cations to
prepare 1-alkylated 2-azabicyclo[3.3.1]nonanes, see:Yamazaki, N.; Suzuki,
H.; Kibayashi, C. J. Org. Chem. 1997, 62, 8280.
Supporting Information Available: Experimental procedures and
characterization of all new compounds. This material is available free
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