Carbon Dioxide → 2-Phenylpropanal

Participants

Reaction Conditions

Reaction Steps

To a 300 mL stainless steel autoclave equipped with two sapphire windows containing Rh(acac)(CO)2 (10.4 mg, 4×10-2 mmol) and (R,S)-BINAPHOS (60 mg, 8×10-2 mmol) were added styrene (2.08 g, 2.0 mmol) and n-undecane (156 mg, 1.0 mmol) (the internal standard for GC analysis). The air was replaced by CO through pressurization (2-3 atm) and release for 2-3 times, and CO (7 atm) was introduced followed by H2 (14 atm). The reaction vessel was cooled to -60° C. and CO2 (78 atm) was introduced. The mixture was allowed to stir at 65° C. and 100 atm overnight. The autoclave was cooled to 0° C. and all the gasses were carefully released. The GC analysis showed that the conversion of the reaction was 91% and the ratio of 3-phenylpropanal to (R)-2-phenylpropanal was 1:12.5. The enantiomeric purity of 2-phenylpropanal thus formed was determined to be 85% enantiomeric excess by converting it to (R)-2-phenylpropanol followed by esterification with (S)-methoxy(trifluoromethyl)phenylacetyl chloride in the presence of triethylamine in CH2Cl2, and subjecting the resulting chiral ester to the 1H NMR analysis.

Provenance & Evidence