Toluene → 2-Formyl-2,5-dimethyl-hexanoic acid ethyl ester

Temperature

-78 °C

A solution of 2-methyl-2-(3-methyl-butyl)-malonic acid diethyl ester (500 mg, 2.05 mmol) in anhydrous dichloromethane (4 mL) was stirred at −78° C. under a blanket of nitrogen and treated dropwise via syringe with a 1.0 M solution of diisobutylaluminum hydride in toluene (4.1 mL, 4.1 mmol) over a period of 15 min. The reaction was stirred for 4 h at −78° C. and quenched sequentially with a saturated aqueous ammonium chloride solution (3 mL) and a 4% aqueous hydrochloric acid solution (3 mL). The resulting gelatinous suspension was allowed to warm to 25° C. and was filtered through a sintered glass funnel. The filtrate was concentrated in vacuo. The resulting crude oil was purified by flash column chromatography (Teledyne Isco RediSep column; 0-20% ethyl acetate in hexanes) to afford the desired product, 2-formyl-2,5-dimethyl-hexanoic acid ethyl ester (150 mg, 0.75 mmol, 36%), as a clear oil. 1H NMR (400 MHz, CDCl3) δ: 0.89 (d, 6H, J=6.9 Hz), 1.07-1.15 (m, 2H), 1.23-1.26 (m, 3H), 1.28 (s, 3H), 1.52 (septet, 1H, J=6.6 Hz), 1.83-1.92 (m, 2H), 4.21 (q, 2H, J=6.9 Hz), 9.69 (s, 1H).

1. customquenched sequentially with a saturated aqueous ammonium chloride solution (3 mL)
2. temperatureto warm to 25° C.
3. filtrationwas filtered through a sintered glass funnel
4. concentrationThe filtrate was concentrated in vacuo
5. customThe resulting crude oil was purified by flash column chromatography (Teledyne Isco RediSep column; 0-20% ethyl acetate in hexanes)

ORD record

ord-968bba659a8d46149d120f0a85aa58dc

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08097613B2