Olefins from Crowded Carbonyl Compounds with tert-Butyllithium (tert-Butylmagnesium Chloride)/Thionyl Chloride. Study of Carbocationic Reaction Intermediates and Rearrangement-Cleavage under Stable Ion Conditions Using 13C NMR Spectroscopy

Article abstract of DOI:10.1021/jo00293a023

Crowded carbonyl compounds when reacted with tert-butyllithium or tert-butylmagnesium chloride followed by thionyl chloride treatment give in an one-pot reaction olefins in good to excellent yields.In the case of highly crowded tertiary systems the reaction occurs either by rearrangement followed by the loss of a tert-butyl group (as isobutylene) or rearrangement accompanied by deprotonation, indicating the carbocationic nature of the process.The nature of the intermediate carbocation and their cleavage-rearrangement process was probed in SbF5/SO2ClF solution of thecorresponding alcohols under stable ion conditions using 13C NMR spectroscopy.