Efficient Oxa-Diels–Alder/Semipinacol Rearrangement/Aldol Cascade Reaction: Short Approach to Polycyclic Architectures

A novel carbon electrophile induced
intermolecular oxa-Diels–Alder/semipinacol
rearrangement/aldol cascade reaction of allylic silyl ether with β,γ-unsaturated
α-ketoester has been developed under the promotion of SnCl4. This highly efficient transformation enables the quick construction
of polycyclic architectures with up to five contiguous stereogenic
centers in a single operation with moderate to good yields as well
as high diastereoselectivity and would provide versatile short approaches
to frameworks and/or analogues of numerous biologically important
polycyclic natural products.