Boron and tin(II) 2-furanolates generated in situ from 2-(5H)-furanone and α-angelica lactone undergo regioselective aldolization with aldehydes to furnish the corresponding 2-(1′-hydroxyalkyl)butenolides in good yields; a new formal synthesis of (±)-litsenolide C1 and (±)-dihydromahubanolide is described.