Highly enantioselective [3+2] annulation of cyclic enol silyl ethers with donor-acceptor cyclopropanes: Accessing 3a-hydroxy [n.3.0]carbobicycles
A new fuse: The title reaction was realized using a new bisoxazoline (BOX)/CuII catalyst. This reaction works well with cyclic enol silyl ethers of different sizes, and can be extended to dienol and benzene-fused substrates, thus providing an effective and general access to a range of 3a-hydroxy [n.3.0]carbobicycles which are found as a core structure in many natural products. TBDPS=tert-butyldiphenylsilyl.