The gas-phase Wittig–oxy Cope rearrangement of deprotonated diallyl ether

Abstract

Collisional activation of deprotonated diallyl ether is found to give major products formd by competitive losses of H₂, C₃H₄O and C₄H₆. Products are rationalised in terms of the Wittig-oxy Cope rearrangement sequence CH₂CH–H–O–allyl →(CH₂CH)(CH₂CH–CH₂)CHO^–→ CH₂CH(CH₂)₂ CHCHO → products. The spectrum of CH₂CH–CDOCD₂CHCH₂ shows the operation of both 1,2- and 1,4-Witting rearrangements, while that of CH₂CH–CDO–allyl shows proton transfer (to form CH₂CH–CHD–O–HCHCH₂) to be a minor process.