Diverse Fates of β‐Silyl Radical under Manganese Catalysis: Hydrosilylation and Dehydrogenative Silylation of Alkenes

Manganese‐catalyzed hydrosilylation of alkenes has been underdeveloped for a long time. Herein, we describe a general, chemo‐ and regio‐ selective hydrosilylation of alkenes by using the Mn(CO) 5 Br catalyst with ample substrate scopes. Meanwhile, dehydrogenative silylation of aryl olefins can be selectively achieved upon the catalysis of dinuclear Mn 2 (CO) 10 . Mechanistic experiments revealed diverse fates of the common intermediate β‐silyl radical, namely, hydrogen atom transfer (HAT) for the hydrosilylation and organometallic β‐H elimination for the dehydrogenative silylation of olefins.