119648-98-5Relevant academic research and scientific papers
Terpenoid Ether Formation in Superacids
Carr, Graham,Dean, Cristopher,Whittaker, David
, p. 351 - 354 (1988)
A number of terpenoid bicyclic ethers have been prepared by cyclisation of suitable precursors in fluorosulphuric acid-sulphur dioxide.The products are formed under a mixture of thermodynamic and kinetic control, and five-, and six-, and seven-membered-ring ethers are obtained.Both primary and secondary alcohols have been cyclised by attack of the hydroxy group on carbocation centres generated by protonation of alkenes or ionisation of tertiary alcohols; tertiary alcohols ionise too readily to provide an etheral oxygen atom.Reaction of the unsaturated secondary alcohol dihydrocarveol (2) with antimony pentafluoride in sulphur dioxide gives the ether by a reaction which may not involve a carbocation, and hence may be suitable for ether formation from substrates which rearrange readily in acids.
