Cyclopropanecarboxylic acid, 2-formyl-, ethyl ester, (1S-trans)- (9CI) synthesis

Yield:109716-61-2 91%

Reaction Conditions:

with pyridinium chlorochromate in dichloromethane at 20; for 4.5 h;Cooling with ice;

Steps:

22 Ethyl (1 S,2S)-2-formylcyclopropanecarboxylate

To an ice cooled solution of ethyl (lS,2S)-2- (hydroxymethyl)cyclopropanecarboxylate (12.25 g, 84.9 mmol,) in DCM (425 mL), add pyridinium chlorochromate (26.09 g, 118.6 mmol) in one portion. After 30 minutes remove ice bath and stir at room temperature for 4 hours. Add water (200 mL) and filter through diatomaceous earth. Rinse with additional water (100 mL) and DCM (800 mL). Suspend the diatomaceous earth cake in DCM and filter. Repeat this operation twice. Combine organics, separate the water layer, and filter the organics through a pad of silica. Rinse with additional DCM and evaporate solvent under reduce pressure to afford the title compound (11.0 g, 91%) as an oil. 1H NMR (400.13 MHz, CDCh): 1.30 (t, J=7.3 Hz, 3H), 1.57-1.50 (m, 1H), 1.60-1.65 (m, 2H), 2.26-2.30 (m, 1H), 2.45 (td, J=9.0, 4.2 Hz, 1H), 4.13-4.22 (m, 3H), 9.32 (d, J=4.2 Hz, 1H).

References:

WO2019/168744,2019,A1 Location in patent:Page/Page column 43