Allylmagnesium Halides Do Not React Chemoselectively Because Reaction Rates Approach the Diffusion Limit

摘要: Competition experiments demonstrate that additions of allylmagnesium halides to carbonyl compounds, unlike other organomagnesium reagents, occur at rates approaching the diffusion rate limit. Whereas alkylmagnesium and alkyllithium reagents could differentiate between electronically or sterically different reacted with most compounds similar rates. Even esters occurred competitive aldehydes. Only in case particularly hindered substrates, such as those bearing tertiary alkyl groups, were slower.