Synthesis of α-Acetyl Lactones; Access to 14-Membered Bislactones by Attempts at Direct Ring Closure

α-Acetyl lactones are accessed by Mukaiyama-Claisen reactions. Attempts at direct 7-membered ring closure, by either intramolecular alkylation of 4-iodobutyl acetoacetate or olefin meta­thesis from allyl 2-allyl-3-oxobutanoate, afford exclusively dimeric 14-membered ring products instead of the expected caprolactones.