Cu-Catalyzed Asymmetric Allylic Substitution with Boron Nucleophiles

Significance

The first example of a Cu(I)-catalyzed asymmetric allylic substitution with non-carbon nucleophiles is presented. Using bis(pinacolato)diboron, a Cu(I) source, and a chiral ligand, optically active α-chiral allylboronates can be synthesized in moderate yields and excellent enantio­selectivities. The paper presents a limited number of examples and the reaction appears to have high sensitivity to steric effects since it does not proceed with a bulky isopropyl group on the alkene of the allylic carbonate. However, the synthetic utility of the products is demonstrated by a Lewis acid mediated stereoselective addition to an aldehyde with high enantio- and E/Z selectivity.