Cyclopropene Derivatives as Precursors to Enantioenriched Cyclopropanols and n-Butenals Possessing Quaternary Carbon Stereocenters

The diastereoselective carbocupration reaction of cyclopropenylmethyl ethers followed by addition of oxenoid leads to the formation of diastereo‐ and enantiomerically enriched 2,2,3,3‐tetrasubstituted cyclopropanol derivatives. Ring fragmentation of the copper cyclopropanolate leads to acyclic butenal derivatives possessing enantiomerically enriched α‐quaternary carbon stereocenters in a single‐pot operation. Make it two: The diastereoselective carbocupration reaction of cyclopropenylmethyl ethers followed by addition of oxenoid leads to the formation of diastereo‐ and enantiomerically enriched 2,2,3,3‐tetrasubstituted cyclopropanol derivatives (see scheme). The ring fragmentation of the copper cyclopropanolate leads to acyclic butenal derivatives possessing enantiomerically enriched α‐quaternary carbon stereocenters.