Enantioselective nickel-catalyzed cross-coupling reactions of trialkynylindium reagents with racemic secondary benzyl bromides

The first enantioselective sp-sp(3) cross-coupling reaction between alkynyl organometals and racemic benzyl bromides is reported. The coupling is performed at room temperature by using NiBr2-diglyme and (S)-(iPr)-Pybox as the catalytic system and trialkynylindium reagents as nucleophiles. The reaction is stereoconvergent, both enantiomers of the racemic benzyl bromide are converted into one enantiomer of the product, and stereospecific. The reaction takes place efficiently in good yields and with high atom economy, as the triorganoindium reagents transfer the three organic groups attached to indium (only 40 mol % of R3In is used).