Reaction of 1,2-Cyclic Sulfites with Some Soft Nucleophiles. Formation of Enantiomerically Pure gamma-Lactones.
摘要:
The reaction between 1,2-cyclic sulfites and soft carbon centered nucleophiles has been investigated. For monosubstituted cyclic sulfites, the main products were gamma-lactones or acetoxy esters. For 1,2-disubstituted cyclic sulfites. cyclopropanes. carbonate and dioxolanes were the main products, A mechanistic rationale for the product formation is presented.
Nucleophilic Reactions between Cyclic 1,2-Sulfites and Chloride Ions.
摘要:
When cyclic 1,2-sulfites are ring opened by chloride ion, the chlorohydrins are formed with low regio and stereo-selectivity. The mechanisms involved in the process were investigated by measuring the stereochemical outcome of the reactions. The results showed that reversible inversion pathways (S(N)2 reactions) and a retention pathway (S(N)2i reaction) gave rise to the loss in ee in both the chlorohydrins and in the cyclic 1,2-sulfites.