Addition Reactions

This Chapter Contains Sections titled: 2 + 2-Cycloaddition 2 + 3-Cycloaddition 2 + 4-Cycloaddition Miscellaneous References This chapter presents an extensive review of the use of organocatalysts, such as diarylpropinol silyl ethers, in asymmetric cycloaddition reactions. The review includes 2+2-, 3+2-, and 4+2-cycloadditions which do not require the loss of a leaving group to form the cyclic compound. The chapter reports a comprehensive review of gold-catalysed enantioselective annulations including cycloadditions, cyclizations of C–C multiple bonds with tethered nucleophiles, cycloisomerization or cyclization of enynes, and tandem annulations. The photosensitized regioselective 2+2-cycloaddition of cinnamates, chalcones, and styrenes produced substituted cyclobutanes in high yields and good regioselectivity. The stereoselective organo-catalysed 3+2-cycloaddition of donor–acceptor cyclopropanes with mono- and poly-substituted nitroolefins produced functionalized cyclopentanes with three contiguous stereocentres in high yields and stereoselectivity. A review of the 4+2-cycloaddition reactions of ynamines and ynamides providing complex aromatics and N-containing heterocycles in a single step has been published.