Allenes. Part XXI. The preparation of 1,1-dialkyl-3-iodoallenes and 1,1-dihalogenoallenes

Abstract

1,1-Dialkyl-3-iodoallenes were prepared in good yield from 1,1-dialkylprop-2-yn-1-ols and 45% hydriodic acid in the presence of copper(I) iodide. Several 1-bromo- and 1-chloro-alk-1-yn-3-ols were converted by hydrogen bromide–copper(I) bromide or thionyl chloride into the corresponding 1,1-dibromo-, 1-bromo-1-chloro- or 1,1-dichloro-allenes. The mechanism of the reaction is discussed and the spectroscopic properties of these new compounds are reported.