2,6-Lutidine → 3-Triisopropylsilanyloxy-cyclopentanecarboxylic acid ethyl ester

Participants

Reaction Steps

A solution of 3-hydroxy-cyclopentanecarboxylic acid ethyl ester (prepared as described in PCT Int. Appl. 2008131946, 3.180 g, 20.1 mmol) in dichloromethane (100 mL) was subsequently treated with 2,6-lutidine (4.7 mL, 40.2 mmol) and triisopropylsilyl trifluoromethanesulfonate (8.1 mL, 30.15 mmol). After stirring for 3.5 h, the reaction was quenched with pH 4 buffer. The aqueous layer was extracted with dichloromethane. The organics were combined, filtered through a phase separator and the volatiles were removed in vacuo. The residue was purified by silica gel chromatography using a 100 g Isolute cartridge eluted with a continuous gradient of iso-hexanes/diethyl ether 1:0 to 9:1 to afford the title compound (6.15 g, 97%) as a light yellow oil and as a 3.5:1 mixture of diastereoisomers. 1H NMR (300 MHz, CDCl3): δ 1.04-1.08 (m, 27H), 1.27 (t, J=7.1 Hz, 4H), 1.70-2.00 (m, 5.2H), 2.04-2.21 (m, 2.6H), 2.66-2.79 (m, 1H), 2.97-3.10 (m, 0.3H), 4.14 (q, J=7.1 Hz, 2.6H), 4.29-4.39 (m, 1H), 4.43-4.50 (m, 0.3H).

Provenance & Evidence