An Efficient Strategy for the Synthesis of a,a’-cis and trans-Disubstituted Medium Ring Ethers

An asymmetric alkylation-ring-closing metathesis strategy was developed for the construction of a,a’-disubstituted medium ring ethers. The approach features an asymmetric alkylation of highly functionalized a-alkoxy acyl oxazolidinones followed by ring closure effected by Grubbs’ ruthenium catalyst. The relationship between diene conformation and the rate of ring-closure was examined.