Regio- And diastereoselective reactions of chiral secondary alkylcopper reagents with propargylic phosphates: Preparation of chiral allenes

Abstract

The diastereoselective SN2'-substitution of secondary alkylcopper reagents with propargylic phosphates enables the preparation of stereodefined alkylallenes. By using enantiomerically enriched alkylcopper reagents and enantioenriched propargylic phosphates as electrophilesanti-SN2'-substitutions were performend leading to a-chiral allenes in good yields with excellent regioselectivity and retention of configuration. DFT-calculations were performed to rationalize the structure of these alkylcopper reagents in various solvents, emphasizing their configurational stability in THF.