Grignard reaction
A patented process for the manufacture of rosefuran via condensation of 3-formylpropionic acid methyl ester with crotonaldehyde has been described. The intermediate ketoaldehyde is cyclized to a furan derivative which is converted to rosefuran in 33% overall yield via Grignard reaction to give 2-methyl-4-(3-methyl-2-furanyl)-2-butanol followed by dehydration.