Intramolecular Anti‐Carbolithiation of Alkynes: Stereo‐Directing Effect of Lithium‐Coordinating Substituents

This paper presents the results of our investigations on the stereochemical course of intramolecular carbolithiation of alkynes. It is shown that the presence of a lithium‐chelating propargylic substituent completely reverses the otherwise favored syn‐process towards an anti‐addition. The reaction was studied by both experiment and computation. Electrophile trapping and domino process led to the stereocontrolled preparation of tetrasubstituted alkylidene indenol derivatives. Additionally, preliminary results on challenging desymmetrizing carbolithiation mediated by an external chiral ligand of lithium are provided.