Asymmetric Catalysis With Azomethine Ylides

Azomethine ylides are important reaction intermediates in asymmetric catalytic reactions. Recently years, our research group have done a lot of research in the asymmetric1.3-dipolar cycloaddition of azomethine ylides, and have achieved many excellent results. In this thesis, we designed various novel asymmetric catalytic reactions to expand the application of azomethine ylides, the main contents are as followed:1) The first CuBF4/TF-BiphamPhos-catalyzed1,3-dipolar cycloaddition of azomethine ylides with MBH adducts providing the highly substituted pyrrolidines bearing a unique quaternary and two tertiary stereogenic centers in good yields (up to97%) and excellent diastereo/enantioselectivity (>20:1dr and up to97%ee).2) Cu(I)-catalyzed tandem Michael addition-elimination of α-substituted imino esters with Morita-Baylis-Hillman carbonates followed by simple deprotection/lactamization protocol providing biologically active pyroglutamates in good yields (up to73%overall3steps) and excellent enantioselectivities (up to99%ee). In order to explain the asymmetric catalyzed tandem Michael addition-elimination, a possible transition state model was proposed.3) We have successfully developed the first CuBF4/TF-BiphamPhos-catalyzed tandem Michael addition-elimination reaction of homoserine lactone derived cyclic azomethine ylides followed by simple deprotection/lactamization protocol constructing spiro-[γ-butyrolactam-γ-butyro lactone] in good yields (up to88%)and excellent diasterco-/enantioselectivity (>20:1dr and up to94%ee).4) As the strategy of projects2and3, we employed the MBH-typed compounds bearing a CF3group at the end of the alkene as substrates to carry out the Michael addition-elimination reaction with azomethine ylides. as a consequence, we can introduce a CF3group and an additional chiral carbon center to pyroglutamates.5) An unprecedented Cu(Ⅰ)-catalyzed asymmetric [6+3] cycloaddition of tropone with azomethine ylides has been successfully developed, which provides the efficient and facile access to optically active bridged azabicyclo[4,3,1]decadiene derivatives in high yields with excellent diastereo-/enantioselectivity (>20:1dr and up to99%ee); To elaborate these asymmetric catalyzed [6+3] cycloaddition reaction, a plausible reaction mechanism and transition state model were proposed.