AN INTRAMOLECULAR NUCLEOPHILE-CATALYZED ALDOL-LACTONIZATION (NCAL) REACTION OF S-ARYL-(E)-6-OXOHEX-2-ENETHIOATE WITH N,N-4-DIMETHYLAMINOPYRIDINE N-OXIDE

摘要

We have developed an intramolecular nucleophile-catalyzed aldol-lactonization (NCAL) reaction of S-aryl-(E)-6-oxohex-2-enethiolate with N,N-4-dimethylaminopyridine N-oxide (DMAPO) to afford densely functionalized bicyclic beta-lactones in moderate yield. This unique transformation may be explained in terms of nucleophilic substitution of the S-aryl moiety by DMAPO, followed by 1,4-addition of aryl thiolate to generate a zwitterionic enolate and an intramolecular C-C bond-forming reaction (aldol-lactonization).