Stereoselective Cascade Reactions of Donor-Acceptor Cyclopropanes with m-N,N-Dialkylaminophenyl α,β-Unsaturated Carbonyls: Diastereoselective Synthesis of cis- and trans-Tetralins

The ytterbium(III) triflate [Yb(OTf)3]‐catalyzed diastereoselective cascade reaction of m‐N,N‐dimethylaminophenyl α,β‐unsaturated carbonyls with cyclopropane 1,1‐diesters under mild reaction conditions afforded highly substituted cis‐ and trans‐tetralins. The reaction of m‐N,N‐dimethylaminophenyl α,β‐unsaturated ketones with cyclopropane 1,1‐diesters provided tetralins with a trans orientation of the 1,4‐substitutents on the cyclohexyl ring; cis‐tetralins were obtained from m‐N,N‐dimethylaminophenyl substituted methylidenemalonates with high diastereoselectivities.