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Synlett 2003(7): 1055-1057
DOI: 10.1055/s-2003-39303
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

A Comparative Study of the Synthesis of C2-Symmetric Chiral 2,2′-Biaziridinyls

Tõnis Kanger*a, Kerti Ausmeesa, Aleksander-Mati Müüriseppa, Tõnis Pehkb, Margus Loppa
a Department of Chemistry, Tallinn Technical University, Akadeemia tee 15, Tallinn 12618, Estonia
Fax: +3726547520; e-Mail: kanger@chemnet.ee ;
b National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia
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Received 17 March 2003
Publikationsdatum:
20. Mai 2003 (online)

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Abstract

Two comparative synthetic routes to new enantiomeric C2-symmetric Boc-protected biaziridinyls from tartaric ester were studied. Simplicity, high enantiomeric purity and high chemical yield of the target compound characterize the proposed methods. Also, unprotected biaziridinyl was synthesized and fully characterized.

Key words

stereoselective synthesis - azides - heterocycles - chiral auxiliaries

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1H NMR (500 MHz, CDCl3) δ 1.44 (18 H, s, t-Bu), 3.05 (2 H, m, CHO), 3.20 and 3.47 (4 H, m, CH2NH), 5.43 (2 H,
br s, NH); 13C NMR (125 MHz, CDCl3) δ 28.29 (q, J = 126.7 Hz, t-Bu), 38.24 (t, J = 126.7 Hz, CH2NH), 55.10 (d, J = 175.0 Hz, CHO), 79.69 (s, t-Bu), 156.23 (s, CONH).CI-MS m/z (%) 303 (3) (M + H)+, 191 (100), 173 (39), 116 (63).

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General experimental procedure for direct ring closure: To a solution of dimesylate 6 (0.46 mmol) in anhydrous THF (5 mL) NaH (0.96 mmol, 60% dispersion in mineral oil) was added portion wise at 0 °C under Ar atmosphere. The mixture was stirred at room temperature for 5 h, quenched with water, extracted with EtOAc. The solvent was evaporated and the mixture was purified by column chromatography on silica gel affording bisaziridine 7 (0.39 mmol) in 85% yield. 1H NMR (500 MHz, CDCl3) δ 1.43 (18 H, s, t-Bu), 2.14 (2 H, d, J = 3.3 Hz, H-3,3′), 2.28 (2 H, d, J = 6.1 Hz, H-3,3′), 2.71 (2 H, m, H-2,2′); 13C NMR (125 MHz, CDCl3) 27.82 (q, J = 127 Hz, t-Bu), 29.51 (dd, J = 176.8 Hz, 170.5 Hz, C-3.3′), 35.47 (d, J = 169 Hz, C-2,2′), 81.36 (s, t-Bu), 161.88 (s, CON). MS m/z (%) 285 (5) (M + H)+, 229 (18), 173 (72), 129 (18), 57 (100), 41 (76). [α]D 20 +175 (c 4.4, MeOH)

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General experimental procedure for the Staudinger reaction: To a solution of azidodiol 2 (1.1 mmol) in anhydrous acetonitrile (6 mL) PPh3 (2.3 mmol) was added and the solution was stirred for 3 h at room temperature followed by reflux for 4 h. The mixture was cooled in the ice-bath and Et3N (2.3 mmol) and Boc2O (2.25 mmol) were added. The mixture was stirred overnight at room temperature, the solvent was evaporated and the residue was triturated with Et2O. The organic layer was purified by column chromatography on silica gel affording target compound 7 in 71% yield.

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General experimental procedure for the Staudinger reaction using polymer-supported PPh3: To a solution of azidodiol 2 (1.1 mmol) in anhydrous acetonitrile (12 mL) polymer-supported PPh3 (2% DVB, 3.3 mmol) was added and the solution was stirred for 3 h at room temperature followed by reflux for 11 h. The resin was filtered, the filtrate was evaporated and the residue was purified on aluminum oxide(basic) affording target compound 10 in 25% yield. MS m/z (%); 83 (54), 68 (32), 56 (100), 42 (61); HRMS calcd for C4H7N2 (M - H)+ 83.0609, found 83.0612.