Michael acceptor in organic synthesis. Prepn: W. H. Perkin, Jr., J. L. Simonsen, J. Chem. Soc. 1907, 816. IR spectrum and rotational isomerism study: S. W. Charles et al., J. Mol. Struct. 26, 249 (1975). Use in photochemical addition reactions: G. Büchi, S. H. Feairheller, J. Org. Chem. 34, 609 (1969); in Michael addition reactions: A. Hong, J. M. Friedman, Synth. Commun. 27, 2971 (1997); in halo aldol reactions with aldehydes: D. Chen et al., Eur. J. Org. Chem. 2004, 3330. Review of use as a peptide coupling reagent: B. Iorga, J.-M. Campagne, Synlett 2004, 1826-1828.