| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 106 === Asymmetric organocatalytic tandem reactions are environmental friendly and highly efficient synthetic strategies by utilizing chiral organocatalyst, which allow for the construction of multiple new chemical bonds and stereogenic centers in short time. Enyne, a highly functionalized reagent, was mostly activated by metal complexes or organocatalysts combined metal reagents to carry out the synthesis reaction according to past literature. However, there is only few reports using non-metal catalysis be published.
In this research, an efficient organocatalytic tandem reaction among 1,3-enynes, pyrazolones and methyl vinyl ketone has been designed that furnishes highly functionalized tetrahydropyranopyrazole with a quaternary stereocenter in excellent chemical yields (84-98%) and outstanding stereoselectivities (ee =82-95 % and dr >20 : 1) in the presence of few amount of bifunctional squaramide catalyst and 1,8-diazabicyclo(5.4.0)undec-7-ene through an Michael/oxa-Michael/Michael tandem sequence. Hope that this synthesis method will contribute to the relevant academic and industrial applications in the future, and the related synthetic applications are still in progress in our laboratory.
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