Tert-Butylamine → HCID 2734514, compound

Participants

Reaction Conditions

Reaction Steps

A solution of the tert-butylamine salt of 2-isopropylidenesuccinic acid 1-methyl ester (162 g, 0.66 mol) in methanol (800 mL) was transferred to a 2 L high pressure hydrogenation vessel and degassed by pressurizing and venting four times with 10 bar of hydrogen. The vessel was then cooled to 0° C. and a solution of [Rh(COD)(S,S)-Me-BPE]OTf (0.80 g, 0.0013 mmol) in methanol (10 mL) was added through the solvent port. The reaction was purged again with hydrogen and stirred at 0° C. under a pressure of hydrogen of 10−7 bar. After 22 hours, the temperature was allowed to raise to room temperature, the vessel was vented in a fume hood, the reaction mixture was transferred to a round-bottomed flask and the solvent was evaporated under reduced pressure. A sample (1 g) of the resulting solid residue was partitioned between HCl 2N (5 mL) and ethyl acetate (5 mL). The organic layer was dried over MgSO4 and evaporated to give 2-(S)-isopropylsuccinic acid 1-methyl ester, ee 96% by GC. The bulk residue was suspended in ethyl acetate (600 mL) and stirred at room temperature for 48 hours, then collected and dried under vacuum to give 154 g of the tert-butylamine salt of 2-(S)-isopropylsuccinic acid monomethyl ester (yield: 94%). A sample (1 g) of the salt was worked up and analyzed as above, indicating an enantiomeric excess of 99% for the free acid.

Provenance & Evidence