1,8-Diazabicyclo(5.4.0)undec-7-ene → HCID 86755673, compound

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Reaction Conditions

Reaction Steps

To a solution of (1S,2R,3R,5R,6S)-2-azido-3-trifluoromethanesulfonyloxy-bicyclo[3.1.0]hexane-2,6-dicarboxylic acid 2-benzyl ester 6-ethyl ester (XXV) (1.36 g, 2.85 mmol) in THF (5.7 mL) was added DBU (0.47 mL, 3.13 mmol) and the mixture was stirred at -50° C. for 3 h. After dilution with ethyl acetate, the solution was washed with 1 N HCl-sol., sat. NaHCO3 -sol. and brine, followed by drying over MgSO4. Removal of the solvent in vacuum left the crude (1S,2R,5R,6S)-2-azido-bicyclo[3.1.0]hex-3-ene-2,6-dicarboxylic acid 2-benzyl ester 6-ethyl ester (XXVI) (566 mg, 61%) as a brownish oil, sufficiently pure for further transformations. 1H-NMR (250 MHz, CDCl3) □1.27 (3H, t, J=7.1 Hz), 1.76 (1H, t, J=3.5 Hz), 2.59 (1H, dt, J=7, 3.5 Hz), 2.67 (1H, ddd, J=7, 3.5, 2 Hz), 4.14 (2H, q,J=7.1 Hz), 5.27 (2H, s), 5.53 (1H, d, J=5.5 Hz), 6.25 (1H, dd, J=5.5, 2Hz), 7.37 (5H, s); MS[ISP] 345 (M+NH4+); □D20 -7183.54° (c=1.08, CHCl3).

Provenance & Evidence