The four-centre reactions of alkanol–alkoxide negative ions with alkyl ethers and orthoacetates. An ion cyclotron resonance study

Abstract

Alkoxide–alkanol negative ions [R¹O^–⋯ HOR²] react with carbon ethers (e.g., Me₃COR³) by the four-centre reactions [R¹O^–⋯ HOR²]+ Me₃COR³→[R²O^–⋯HOR³]+ Me₃COR¹, and [R¹O^–⋯ HOR²]+ Me₃COR³→[R¹O^–⋯ HOR³]+ Me₃COR². The former reaction predominates when R¹ < R². In the case of di- and tri-ethers, the four-centre reaction can, in principle, compete with the alternative six-centre reaction. For example, for Me₂C(OR³)₂, [R¹O^–⋯HOR²]+ Me₂C(OR³)₂→ Me₂CO + R¹OR³+[R²R^–⋯ HOR³]. Evidence is presented which shows that the six-centre reaction does not occur.