Photolysis of diazocyclopentadiene : Reactivity of cyclopentadienylidene in sulfides and ethers

Abstract

Photolysis of diazocyclopentadiene in the presence of dimethyl, diethyl and tetramethylene sulfides gave the corresponding sulfonium cyclopentadienylide. But the ylides from diisopropyl and di-t-butyl sulfides were unstable, and the reaction mixture gave the CH and CS insertion products of cyclopentadienylidene and olefin elimination products. Reaction of diazocyclopentadiene in ethers gave the CH insertion and some CO insertion products. For diethyl ether, the insertion ratio into secondary and primary CH bonds was 19:1. For tetrahydrofuran, both α and β-CH insertion products were observed in ratio of 3:0. Photolysis of diazocyclopentadiene in allylic ethers gave the addition product of the carbene to the double bond, but in allylic sulfides gave both CS insertion and addition products of the carbene.