Stereoconvergent Aminoboration of (/)-Mixed Alkenes via Bimetallic Asymmetric Relay Catalysis.

Methods for the enantioselective transformations of alkenes constitute one of the most frequently used strategies in synthetic chemistry. Despite tremendous advancements in this domain, achieving the asymmetric difunctionalization of (/)-mixed alkenes in a stereoconvergent manner poses a formidable challenge. Here, we present a bimetallic relay-catalyzed asymmetric aminoboration of (/)-isomer mixtures with an engineered ferrocene-oxazoline (FcPHOX) ligand. The reactions proceed efficiently and exhibit a broad substrate scope with excellent enantio- and diastereoselectivity (generally >90% e.e. and up to 99:1 d.r.), affording chiral β-aminoalkylboronates as the key synthons for important bioactive molecules. The synthetic potential of this method is highlighted by the late-stage modification of complex molecules, versatile utility of these products, stereodivergent synthesis of four stereomers, and a sequence stereoconvergent aminoboration direct from propylbenzene. Experimental studies and density functional theory (DFT) calculations were conducted to elucidate the roles of two metal catalysts and crucial effect of the engineered ligand in origins of excellent enantio- and diastereoselectivities.