Ammonium Chloride → alpha-Ethynyl-4,4-dimethylchroman-8-methanol

Participants

Reaction Steps

7.6 ml (54.0 mmol) of trimethylsilylacetylene and 50 ml of THF are introduced into a three-necked flask. A solution of 22 ml (54.0 mmol) of n-butyllithium (2.5M in hexane) is added dropwise at −78° C. under a stream of nitrogen and the mixture is allowed to return to room temperature. The reaction mixture is introduced dropwise into a cold (−78° C.) solution composed of 9.30 g (49.0 mmol) of 4,4-dimethylchroman-8-carbaldehyde and of 50 ml of THF. The reaction mixture is allowed to return to room temperature, poured onto an aqueous ammonium chloride solution and extracted with ethyl ether and the organic phase is separated by settling, dried over magnesium sulphate and evaporated. 14.00 g (100%) of the expected compound are obtained in the form of a yellow oil. 3.00 g (10.0 mmol) of this oil are mixed with 50 ml of THF, and 11.5 ml (12.6 mmol) of a tetrabutylammonium fluoride solution (1.1M in THF) are added dropwise. The reaction mixture is stirred at room temperature for one hour, is poured into water and extracted with ethyl ether and the organic phase is separated by settling, dried over magnesium sulphate and evaporated. 2.30 g (100%) of the expected compound are collected in the form of a colourless oil.

Provenance & Evidence