Methyl iodide → Ethyl 8-methyl-1,4-dioxaspiro[4.5]decane-8-carboxylate

Temperature

-78 °C

Ethyl 1,4-dioxaspiro[4,5]decane-8-carboxilate (2) (5.8 g) was dissolved under a nitrogen atmosphere in dry THF (60 mL) and cooled in a dry ice/isopropanol bath to −78° C. LDA (2M solution in THF/n-heptane/ethylbenzene, 20 mL, 40 mmol) was added dropwise to the stirred solution and the mixture was allowed to warm to room temperature for 30 minutes. The reaction mixture was again cooled to −78° C. and to it was added a solution of iodomethane (5.5 g, 39 mmol) in dry THF (15 mL) using a syringe pump over 20 minutes. This mixture was stirred at −78° C. for 1 h. The reaction mixture was allowed to reach room temperature. The reaction mixture was then diluted with ethyl ether (100 mL) and the organic layer was washed with saturated aqueous ammonium chloride solution (2×50 mL) and brine (1×50 mL), then dried over magnesium chloride, filtered, and concentrated in vacuo to give a yellow-brown oil (8 g). The oil was purified by flash column chromatography [petroleum ether-ethyl ether (2:1)] to give 3 (5.22 g, 85%) as a colorless oil: 1H NMR (CDCl3) δ 4.14 (2H, q, J=7.1 Hz), 3.93 (4H, s), 2.13 (2H, m), 1.64 (6H, m), 1.25 (3H, t, J=7.1 Hz), 1.18 (3H, s); 13C NMR (CDCl3) δ 177.2, 108.7, 64.4, 60.6, 42.5, 33.1, 32.3, 26.2, 14.4.

1. temperatureto warm to room temperature for 30 minutes
2. temperatureThe reaction mixture was again cooled to −78° C. and to it
3. customover 20 minutes
4. customto reach room temperature
5. washthe organic layer was washed with saturated aqueous ammonium chloride solution (2×50 mL) and brine (1×50 mL)
6. dry with materialdried over magnesium chloride
7. filtrationfiltered
8. concentrationconcentrated in vacuo

ORD record

ord-1b6c75fa623f4230973f5dba250fde40

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09000188B2