The lithiation of primary and secondary dialkylsulfates with an excess of lithium powder in the presence of a catalytic amount of naphthalene (4 mol %) in THF at −78°C leads to the corresponding alkyllithium reagents (1:2 molar ratio) which react with different electrophiles, mainly carbonyl compounds, to yield after hydrolysis, the expected coupling products. This methodology represents an indirect
Synthesis of substituted cyclopropanes from 1,3-diols through the corresponding cyclic sulfates
作者:David Guijarro、Miguel Yus
DOI:10.1016/0040-4020(95)00708-g
日期:1995.10
The reaction of different cyclicsulfates 2 (easily prepared from the corresponding 1,3-diols 1 following the Sharpless methodology) with an excess of lithium powder and a catalytic amount of DTBB (5 mol %) leads to the corresponding substituted cyclopropanes 3 through a γ-elimination process, the sulfate ion acting as leaving group.