One-pot preparation of 2-substituted and 2,3-disubstituted furans from 2-alkynal tetramethylethylene acetals and aldehydes using a divalent titanium reagent Ti(O-i-Pr)4/2 i-PrMgX

Sequential treatment of 2-alkynal tetramethylethylene acetals with a divalent titanium reagent Ti(O-i-Pr)4/2 i-PrMgX and aldehydes gave, after acidic work-up, furans in good to excellent yields, thus providing a new efficient one-pot access to a variety of 2-substituted and 2,3-disubstituted furans including those having a functionalized substituent(s).