Ammonia → 5-(4'Bromophenyl)-4-pentyn-1-al ethylene acetal

Participants

Reaction Conditions

Reaction Steps

4-bromophenylacetylene (10 g, 55 mmol), prepared according to Organic Reactions 5 (1), 50, (1949), in dry dimethyl sulphoxide (7.0 ml) was added to lithium amide (from 66 mmol) of lithium) in liquid ammonia (200 ml). The mixture was stirred for 1 hour at -30° C., 2-(2-bromoethyl)-1,3-dioxolane (10 g, 55 mmol) was added and the mixture was stirred for 2 hours at -30° C. Ammonium chloride (12 g) was added, the ammonia was allowed to evaporate and water (200 ml) was added to the residue. The emulsion was extracted with ether and the organic phase was washed with brine and dried. The solvents were removed and the product purified by dry column chromatography (silica, 5% ether in hexane 1:1 ether:hexane) to give 4.08 g (26% of theory) of 5-(4'bromophenyl)-4-pentyn-1-al ethylene acetal.

Provenance & Evidence