ii)-Catalysed Conjugate Addition Reactions
The second chapter of the book collects the new developments achieved since the beginning of 2004 in asymmetric nickel-catalysed conjugate addition reactions. During the last 10 years, an important number of novel highly efficient enantioselective conjugate additions of various nucleophiles to a wide variety of acceptor-activated alkenes have been developed on the basis of asymmetric nickel(II) catalysis by the very fact of the lower costs of nickel catalysts in comparison with other transition metals. These powerful processes can be considered as one of the most powerful and reliable tools for the stereocontrolled formation of carbon−carbon (and carbon−heteroatom) bonds, as has been demonstrated by the huge number of examples in which it has been applied as a key strategic transformation in total synthesis. Using optically active nickel(II) catalysts, these key reactions can be induced highly enantioselectively. Among them are a range of powerful asymmetric domino reactions initiated by Michael additions.