Carbenoid, electrophilic and carbanionic, nucleophilic character is shown by compounds 1, which bear a lithium atom and an electronegative element X as leaving group at the vinyl carbon center. Now that structural investigations have contributed significantly to their understanding, these ambiphilic, thermally unstable compounds are increasingly being used as reagents for synthetic purposes.
Keywords: Asymmetric synthesis; Lithium; Nucleophilic additions; Synthetic methods; Umpolung.
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