Stereoselective generation of 1,3- and 1,4-dioxy-substituted carbanions by sparteine-assisted deprotonation of chiral precursors: Substrate or reagent control in the synthesis of α, γ- and α,δ-diols

Article abstract of DOI:10.1016/S0040-4039(00)79084-8

The deprotonation of a dicarbamate, derived from (S)-butane-1,3-diol, by sec-butyllithium takes an highly diastereoselective, but opposite, direction in the presence of (-)-sparteine and of tetramethylethylenediamine (TMEDA), respectively. The (S)-pentane-1,4-diol derivative shows the same stereochemical preference under both conditions.