1,2-Dibromoethane → 2-Methyloct-1-en-6-yn-3-ol

Participants

Reaction Steps

Magnesium (14.4 g, 0.6 g atom) was dried in a 250 ml flask fitted with reflux condenser, mechanical stirrer and addition funnel. After initiation of reaction under dry N2 with about one ml ethylene dibromide in 70 ml tetrahydrofuran, 36.0 g (0.30 mole) 2-bromopropene was added dropwise at such a rate as to maintain reflux without external heating. The Grignard solution was then stirred until it cooled to room temperature (30 minutes-1hour). It was then cooled further to -15° in ice-salt, and the total crude 4-hexynal from part (c) above was added dropwise over 15 minutes. The reaction mixture was stirred for 2 hours at room temperature, saturated ammonium chloride solution was added and the product was extracted with ether. There was obtained 23.50 g of 2-methyloct-1-en-6-yn-3-ol (85%, based on 4-methyl hexynoate) as a pale yellow oil.

Provenance & Evidence