Stereoselective Retentive Domino Transmetalations of Secondary Alkyllithium Compounds to Functionalized Secondary Alkylcopper Reagents

Article abstract of DOI:10.1002/anie.201505740

Functionalized secondary alkyllithium reagents obtained by I/Li exchange from the corresponding secondary alkyl iodides undergo two successive transmetalations with Me₃SiCH₂ZnBr.LiBr and CuBr.2LiCl.Me₂S to provide functionalized secondary alkylcopper compounds with high retention of configuration. These alkylcopper derivatives react further with electrophiles such as alkynyl esters, acid chlorides, allylic chlorides, ketals, ethylene oxide, and 3-iodocyclopentanone with high retention of configuration. A related sequence of transmetalations with MeMgI and LaCl₃.2LiCl allows a retentive addition of secondary alkyllithium reagents to acetone. The influence of the solvent on the configurational stability of secondary alkylzinc reagents is described.