Nickel-Catalyzed Enantioselective Reductive Cyclization of 1,3-Dienes Toward α-Chiral Six-Membered Silacycles

Chiral organosilanes are increasingly important in synthetic, medicinal, and materials chemistry. However, the enantioselective synthesis of α-chiral six-membered silacycles remains unexplored. Here, we report two nickel-catalyzed enantioselective reductive [4 + 2] cyclizations of 1,3-dienes using readily available chloromethyl chlorosilane or 1,2-dichlorodisilane as dielectrophiles, proceeding via distinct mechanisms. Our strategy represents the first reductive cyclization involving both C-Si bond and C-C bond formation and enables efficient and highly enantioselective access to α-chiral silacyclohexenes and 1,2-disilacyclohexenes with broad functional group compatibility. Further derivatizations demonstrate the potential of this method for constructing valuable chiral silicon building blocks, underscoring its synthetic utility.