Construction of Polycyclic β-Ketoesters Using a Homoconjugate Addition/Decarboxylative Dieckmann Annulation Strategy.

The construction of arene-fused cyclic β-ketoesters from 2-iodoaryl esters and 1,1-cyclopropane diesters is detailed. The synthetic method takes advantage of a CuI·SMe2-mediated homoconjugate addition followed by a decarboxylative Dieckmann cyclization to afford valuable polycyclic building blocks. Various iodoaryl esters and 1,1-cyclopropane diesters were evaluated, and the limitations of both reactions are discussed. Several mechanistic probes are detailed and synthetic applications are described.