Lewis Acid-Catalyzed Intramolecular [3+2] Cross-Cycloaddition of Donor- Acceptor Epoxides with Alkenes for Construction of Oxa-[n.2.1] Skeletons

of main observation and conclusion The first LA-catalyzed [3 + 2]IMCC of GDA-epoxides with carbon-carbon double bonds has been developed. This provides an efficient and general strategy for construction of bridged oxa-[n.2.1] skeletons. A novel S-N-like mechanism through a carbon-carbon bond cleavage of epoxide ring has been proposed.