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A highly efficient asymmetric hydrogenation of α,β-unsaturated carboxylic acids with tetrasubstituted olefin catalyzed by chiral spiro iridium complexes has been developed for the preparation of chiral α-substituted carboxylic acids in excellent enantioselectivities (up to 99% ee). [ABSTRACT FROM AUTHOR]

Carbon–heteroatom bonds (C–X) are ubiquitous and are among the most reactive components of organic compounds. Therefore investigations of the construction of C–X bonds are fundamental and vibrant fields in organic chemistry. Transition-metal-catalyzed heteroatom–hydrogen bond (X–H) insertions via a metal carbene or carbenoid intermediate represent one of the most efficient approaches to form C–X bonds. Because of the availability of substrates, neutral and mild reaction conditions, and high reactivity of these transformations, researchers have widely applied transition-metal-catalyzed X–H insertions in organic synthesis. Researchers have developed a variety of rhodium-catalyzed asymmetric C–H insertion reactions with high to excellent enantioselectivities for a wide range of substrates. However, at the time that we launched our research, very few highly enantioselective X–H insertions had been documented primarily because of a lack of efficient chiral catalysts and indistinct insertion mechanisms. [ABSTRACT FROM AUTHOR]