Studies On Multicomponent Ractions Via 2-Sulfonyliminooxetane Intermediates

Over the past decade, multicomponent reactions (MCRs) have attracted increasing attention due to the virtue of their convergence, productivity, ease of execution and generally high yields of products. In this context, copper(I)-catalyzed multicomponent reaction has been rapidly developed and achieves significant progresses. In this thesis, recent development of copper(I)-catalyzed MCRs and 2-iminooxetane chemistry is initially reviewd. On this basis, we present three unprecedented MCRs via 2-sulfonyl-iminooxetane intermediates. The major contents involve:1. Beneficiated by the accessible ynamido-metal intermediates from a Cu’-catalyzed azide-alkyne cycloaddition in the presence of stoichiometric amounts of LiOH, a mild and flexible three-component route to conjugated enyne and endiyne scaffolds from terminal alkynes, sulfonyl azides, and ynals was successfully achieved via a formal ^-selective olefination strategy. A plausible mechanism for this approach has aso been proposed. In addition, we had explored the cyclization of the resulted enediynes upon treatment with PⅡd in order to demonstrate their synthestic application.2.3-Alkenyl-oxindoles were synthesized via a copper(Ⅰ)-catalyzed three-compent reaction of terminal alkynes, sulfonyl azides,and N-substituted isatins. A plausible mechanism for this approach has been proposed either. Moreover, we have explored the ring-closure reaction of the product via O-nucleophilic attacking onto the tethered C-C triple bond in the absence of base, giving rise to dihydrofuran derivatives.3. We have developed a distinct copper(Ⅰ)-catalyzed four-component reaction of terminal alkynes, sulfonyl azides, N-substituted isatins, and H2O for the synthesis of 3-substituted-3-hydroxyindolin-2-ones. Upon a control experiment with H2O18 as the substrate, a plausible mechanism was proposed. Two comtigous chiral carbons was generated in this process, and the diasteromeric ratio was determined by]H NMR.