The Asymmetric Organocatalytic Reactions Of Quinone Methides

Quinone methides (QMs) as one of vivid, fascinating and important intermediates have been widely applied in the organic chemistry, material chemistry and biological chemistry. This thesis mainly concerned about the development of asymmetric methodologies of quinone methides. The following four chapters in this dissertation are as follows:Chapter 1:The progress in the chemistry of p-quinone methides (p-QMs) is briefly reviewed, and the corresponding description is divided into four parts including intramolecular cyclization reaction, intermolecular cycloaddition reaction, asymmetric reaction, and its catalytic asymmetric version.Chapter 2:A novel catalytic enantioselective 1,6-congjuate addition/aromatization of para-quinone methides (p-QMs) has been developed with malonates under phase transfer catalysis. A series of synthetically interesting, functionalized diarylalkanes were achieved with good to high yields (up to 96%) and enantioselectivities (up to 99% ee) in most of cases. The reaction also offers an alternative route to asymmetric construction of diarylmethine stereocenters.Chapter 3:The progress in the chemistry of o-quinone methides (o-QMs) is reviewed, and it is divided into six parts including conjugated addition reaction, [4+1] cycloaddition reaction, [4+2] cycloaddition reaction, [4+3] cycloaddition reaction, [4+4] cycloaddition reaction, and miscellaneous reactions.Chapter 4:Asymmetric formal [4+2] cycloaddition of allenoates with in situ generated ortho-quinone methides (o-QMs) is designed and developed under the catalysis of Cinchona alkaloid-derived amines, leading to a series of 4-aryl chromans in excellent enantioselectivities (up to 96% ee) and high yields (up to 80%). This reaction not only enriches the application of ortho-quinone methides in asymmetric catalysis, but also provides a new method for the catalytic asymmetric construction of chroman units extensively existing in many natural products as well as pharmaceutically active compounds.