A convenient synthesis of 2′- and 3′-furyl sugars in which the furan and the sugar parts are directly connected is presented. The key step comprises HF·py-induced cyclization of α,β-unsaturated carbonyl compounds (ketones or aldehydes) possessing terminal hydroxymethylene groups protected as TBDPS ethers. Treatment of such furan derivatives with N-phenylmaleimide under high-pressure conditions (11