Alkynylation of ketones and aldehydes-via alkali metal - alkyne-dihydrocarbyl sulphoxide complexes

摘要

The prepn. of alkynylated aldehydes and ketones is effected by complexing a mono-alkali metal deriv. of a dihydrocarbyl sulphoxide with a Lewis base either, phosphine or sulphide, reacting the liquid complex with an alkyne or substd. alkyne to give a complex of the alkyne alkali metal deriv. with the dihydrocarbyl sulphoxide, and then reacting the complex with the aldehyde or ketone, followed by hydrolysis. Thus lithium dimethyl sulphoxide may be complexed with dimethyl ether, the product reacted with acetylene and the complex thus formed reacted with methyl vinyl ketone to give methylvinyl ethynyl carbinol, of use in the prepn. of Vitamin A. Similarly acrolein may be converted to pent-1-en-4-yn-3-ol. The process is simpler and quicker than known processes and gives improved yields. The products may be used in the prodn. of pharmaceuticals and as brightening agents in electroplating baths.