Transition metal-catalyzed redox-triggered C-C couplings of alcohols via transfer hydrogenation
In the first chapter, the first example of transfer hydrogenative cross-couplings of styrene with primary alcohols is reported. Using RuHCl(CO)(PCy₃)₂ as the precatalyst, AgOTf or HBF₄ as additives, branched or linear adducts with styrene would be generated from benzylic or aliphatic alcohols respectively. In the second chapter, a strategy for asymmetric construction of cyclopropanes is developed. In the presence of phosphine ligand, the nickel(0) catalyst react with enantiomerically enriched 3-aryl-4-vinyl-1,3-dioxanones to form (cyclopropylcarbinyl)nickel(II) species, which then couples with organoboron reagents to generate the cyclopropane in a stereospecific way. In this way, the enantioselective synthesis of tetra-substituted cyclopropanes bearing all-carbon quaternary stereocenters is achieved.