Cyclopentanone → 2-Cyclohexyl-3-oxo-3-(2-oxo-cyclopentyl)-propionic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a −78° C. cold solution of LDA (2 M solution in heptane/ethylbenzene/THF, 15.7 ml, 31 mmol) in THF (96 ml) under an argon atmosphere was added a solution of cyclopentanone (2.78 ml, 31 mmol; CAS Reg. No. 120-92-3) in THF (72 ml) within 25 min. The mixture was stirred for 2 h at −78° C. A solution of 3-benzotriazol-1-yl-2-cyclohexyl-3-oxo-propionic acid ethyl ester (9 g, 29 mmol) in THF (63 ml) was added and the solution was stirred at ambient temperature for 14 h. Ice water was added, the mixture was poured onto ice water/brine 1/1 and extracted two times with TBME. The combined extracts were washed with ice water/brine 1/1 and dried over Na2SO4. After filtration the solvent was removed under reduced pressure to give the title compound (8.8 g; quant.) which was used in the next step without further purification.

Provenance & Evidence