Potassium → (S)-3-cyano-5-methylhexanoic acid

Participants

Reaction Conditions

Reaction Steps

A glass liner is charged with the potassium salt of 3-cyano-5-methylhex-3-enoic acid (from Example 1B) and methanol and placed in a 600 mL PARR hydrogenation vessel. The vessel is purged with nitrogen and then with hydrogen via charging to 60 psi and stirring for 10 minutes to ensure thorough equilibration of gases and releasing of the pressure on five cycles. The vessel is heated to 45° C., and a solution of [(R,R)-MeDuPHOS]Rh(COD)BF4− in deoxygenated methanol (11 mg in 10 mL) is added via syringe. The vessel is again purged with hydrogen and then pressurized to 60 psi with stirring. Periodically, hydrogen is added to maintain the pressure between 50 to 65 psi. Hydrogen uptake ceases after 120 minutes. After 2 hours, the mixture is cooled to room temperature, the pressure is released, and the solvent is removed to give the crude product. A small sample is removed and acidified with 1 N HCl to give (S)-3-cyano-5-methylhexanoic acid. GC analysis shows >99% conversion with 96.7% e.e S isomer.

Provenance & Evidence