Stabilization of singlet ethoxycarbonylnitrene by 1,4-dioxan

Abstract

A study of the solvent polarity and triplet quenching effects on the insertion of ethoxycarbonylnitrene into cyclic ethers demonstrates that the singlet state of the nitrene is stablized by 1,4-dioxan. The lowering of the yield of the triplet nitrene product compared with that of the singlet nitrene product in 1,4-dioxan as solvent supports this postulate. The activation parameters for insertion in the presence and absence of a triplet quencher further support singlet stabilization. This is discussed in the terms of the interaction of the nitrene p orbital with the lone pair electrons of ether oxygen atoms.