A PRACTICAL SYNTHESIS OF ROSEFURAN - FURANS FROM ACETYLENES AND ALLYLALCOHOLS

A new atom-economical synthetic strategy for the synthesis of furans e merges from beta,gamma-unsaturated ketones which are readily available from acetylenes and allyl alcohols by simple additions in the presenc e of a ruthenium catalyst. Dihydroxylation using catalytic osmium tetr aoxide creates a diol that is remarkably prone to cyclize to furans in the presence of an acid catalyst. The novelty of this synthesis lies in the overall strategy whereby furans are available in two steps from allyl alcohols and acetylenes with only water as the byproduct. A str aightforward synthesis of the prized fragrance of oil of rose, rosefur an, from propargyl bromide, acetone, and 1-buten-3-ol in 23% overall y ield illustrates the utility of this new strategy.