Carbon Dioxide → rel-(1R,2R)-2-(4-Bromophenyl)cyclopropanecarboxaldehyde

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Reaction Conditions

Reaction Steps

A solution of the later-eluting, R,R-diastereomer ([(1R,2R)-2-(4-bromophenyl)cyclopropyl]-{(1S,5R,7R)-(10,10-dimethyl-3,3-dioxo-3λ6-thia-4-azatricyclo[5.2.1.01.5]dec-4-yl)}methanone) described in Example 29D (5.2 g, 11.86 mmol) in dichloromethane (100 mL) was stirred under a dry nitrogen atmosphere at −78° C. A 1 M solution of diisobutylaluminum hydride in dichloromethane (26.1 mL, 26.1 mmol) was added dropwise to the mixture. When the addition was complete, the mixture was stirred at −78° C. for 3 hour. Methanol (27 mL) was then added dropwise at −78° C. The dry ice bath was then replaced with an ice water bath and saturated aqueous ammonium chloride was added to quench the mixture. After 10 minutes, the insoluble material was removed by filtration and the organic layer was isolated, dried (MgSO4), and filtered. The filtrate was concentrated under reduced pressure to provide a colorless oil that was purified by column chromatography (9:1 hexane/ethyl acetate). Fractions containing product were combined and concentrated under reduced pressure to provide the title compound. 1H NMR (300 MHz, CDCl3): δ 1.45-1.57 (m, 1H), 1.70-1.78 (m, 1H), 2.11-2.19 (m, 1H), 2.55-2.63 (m, 1H), 6.99 (d, J=9 Hz, 2H), 7.42 (d, J=9 Hz, 2H), 9.35 (d, J=4.5 Hz, 1H). MS (DCl—NH3) m/z 225 (M+H)+, m/z 242 (M+NH4)+.

Provenance & Evidence