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[摘要]：The sensitized photocycloaddition reactions of 6,6'-dimethyl-4,4'[1,7-(1,4,7-trioxaheptyl)]-di-2-pyrone (1a) and 6,6 '-dimethyl-4,4 '-[1,10-(1,4, 7,10-tetraoxadecyl)]-di-2-pyrone (1b) with polyethylene glycol dimethacrylates (2a-d) afforded macrocyclic tetralactones containing two cyclobutane rings. The reactions of la with 2a-d afforded diastereomixtures of macrocyclic crown ether-type structures (3a-d and 3a'-d') possessing 19- to 28-membered rings across the C5-C6 and C5'-C6' double bonds of la. Similarly, 1b reacted with 2a-d to give the corresponding 22- to 31-membered-ring products (4a-d and 4a'-d'). A structure for the key intermediate involved in the formation of compounds 3 and 4 has been proposed. |
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