Synthesis of Functionalized Bicyclic Imines via Intramolecular Azide-Alkene 1,3-Dipolar Cycloaddition
3.87 (m, 1H), 3.66 (s, 3H, CO2CH3), 3.58 (m, 1H), 2.66 (m,
this methodology, including mechanistic insight and
enantioselective version as well as its application to
the total synthesis of different alkaloids are currently
in progress and will be reported in due course.
1H), 2.42 (dd, J=14.8, J=4.6 Hz, 1H, CH2CO2CH3), 2.32
(m, 1H), 2.21 (dd, J=14.8, J=8.8 Hz, 1H, CH2CO2CH3),
2.15–2.08 (m, 2H), 1.95 (m, 1H), 1.87 (m, 1H), 1.68 (m,
1H), 1.49–1.40 (m, 2H), 1.25 (m, 1H); 13C NMR (100 MHz,
CDCl3): d=178.3 (C=N), 173.1 (CO2CH3), 59.1, 53.3, 51.7
(CO2CH3), 42.7, 40.4 (CH2CO2CH3), 31.4 (2C), 28.4, 25.2;
HRMS (ESI): m/z=196.1351, calcd. for C11H18NO2 [M+
H]+: 196.1293; FT-IR (neat) nmax =2949, 2866, 1737, 1652,
1568, 1436, 1234, 1195, 1155, 1099, 1012, 982 cmÀ1.
Experimental Section
Caution: All organic azides should be treated as potential
explosion hazards.
Compound 14a {rac-Methyl 2-[(1R,2S)-2-(3,4-
Dihydro-2H-pyrrol-5-yl)cyclopentyl]acetate}
Acknowledgements
A solution of compound 13a (70 mg, 0.29 mmol) in dry
DMF (13 mL) was heated in a microwave reactor at 1408C
for 2 h. The mixture was cooled to room temperature and
the solvent evaporated under reduced pressure. The crude
reaction mixture was then purified by chromatography
(silica gel, gradient from dichloromethane to 2% methanol
in dichloromethane) to afford compound 14a as a yellow
oil; yield: 48 mg (78%).1H NMR (400 MHz, CDCl3): d=
3.75 (m, 2H), 3.61 (s, 3H), 2.47 (m, 4H), 2.39 (m, 1H), 2.23
(dd, J=14.9, J=8.3 Hz, 1H, CH2CO2CH3), 2.02–1.86 (m,
2H), 1.83 (m, 2H), 1.66 (m, 3H), 1.29 (m, 1H); 13C NMR
We thank the Spanish Ministry of Economy and Competitivi-
ty (Project CTQ2010-19295) for financial support as well as
for the purchase of a QToF-HRMS (Project CTQ2007-
28978-E). I.M. (JAE-Predoc fellowship) thanks the Spanish
National Research Council (CSIC). We are grateful to Prof.
Douglass F. Taber (University of Delaware) for insightful dis-
cussions.
References
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A solution of compound 15a (80 mg, 0.31 mmol) in a mixture
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2.52–2.36 (m, 3H), 2.35–2.25 (m, 2H), 2.19 (m, 1H), 2.01–
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(CO2CH3), 48.1, 40.1, 38.9, 32.7, 30.9, 27.1, 24.3, 21.7, 19.3;
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Adv. Synth. Catal. 0000, 000, 0 – 0
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