Sigmatropic Reactions in Carbanions. I. The 5, 6‐dihydro‐2H‐pyran‐2‐ide cyclopropyl‐enolate rearrangement

Abstract

Abstract Lithiation of 5,6‐dihydro‐2 H ‐pyran ( 7 ) gives a mixture of dihydropyranyllithiums 14 and 2 . 14 rearranges to 2 , and 2 in turn undergoes a [1,4] sigmatropic shift to give the lithium cyclopropyl‐enolate 3 . Lithiation of nerol oxide 6 gives the lithio derivative 24 , which likewise undergoes [1,4] shifts to give cyclopropyl‐enolates 28 and 29 .