Cyclobutanecarboxylic acid, 3-ethyl- → 1-(3-Ethylcyclobutyl)ethanone

関与物質

反応手順

A solution of 6.61 g of 3-ethylcyclobutane-1-carboxylic acid, in 52 ml of distilled ether was stirred under argon at 0°. Methyllithium (85.0 ml of a 1.53 M solution in ether) was added dropwise over a 30 minute period. The reaction mixture was stirred for three hours at 25°, then quenched with 7.3 water-methanol. The layers were separated, and the aqueous layer extracted with ether. The combined organic layers were washed with brine, dried, filtered and the solvents evaporated in vacuo. The resultant oil was distilled (aspirator vacuum) to afford 5.5 g of 1-acetyl-3-ethylcyclobutane, as a clear oil (bp 64°-67°). The material had the following spectral characteristics: nmr (CDCl3) δ 0.80 and 0.82 (3H total, pair of t, each J=7.0 Hz), 1.10 and 1.12 (ca. 1.5H total, pair of s, side product 1-[2-hydroxy-prop-2-yl]-3-ethylcyclobutane), 1.0-2.4 (7 H, m), 2.07 and 2.09 (3H total, pair of s) and 2.7-3.5 ppm (1H, m); ir (CHCl3) 935, 1175, 1370, 1460, 1705, 2870, 2930 and 2970 cm-1, also small 3200-3600 broad and 3600 cm-1 for the side product noted above.

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