Copper‐Catalyzed Regio‐ and Enantioselective Addition of Silicon Grignard Reagents to Alkenes Activated by Azaaryl Groups

A new application of silicon Grignard reagents in C(sp³)?Si bond formation is reported. With the aid of BF₃?OEt₂, these silicon nucleophiles add across alkenes activated by various azaaryl groups under copper catalysis. An enantioselective version employing benzoxazole‐activated alkenes as substrates and a CuI‐josiphos complex as catalyst has been developed, forming the C(sp3)?Si bond with good to high enantiomeric ratios (up to 97:3). The method expands the toolbox for “conjugate addition” type C(sp³)?Si bond formation.