Transition-metal Catalyzed Reactions Of Enynes And Study Toward Synthesis Of Indole Alkaloids: Minfiensine And Phalarine

As multifunctional molecules, enyne compounds have been used as important building blocks for diversity-oriented organic synthesis. Based on this point of view, we have developed several novel transformations of enynes catalyzed by transition metal, and applied tandem reactions of enyne compounds for total synthesis of indole alkaloids:Minfiensine and Phalarine. The following five parts are mainly included:1. A gold(I)-catalyzed condensation reaction of enynols has been developed to construct skipped poly-enynes with unique structure. A base promoted thermocyclization and intramolecular D-A reaction of the polyenynes have also been developed to obtain structurally useful allenes and areno[f]indene compounds. Further investigation demonstrated that one of the areno[f]indene could be used as fluorimetric probe toward mecury ion.2. Regiodivergent annulations of alkynyl indoles have been developed and tuned by protective groups through gold catalysis. With electron-donating protective groups, the substrate followed a C3-selective annulation and gave structurally interesting tetrahydro-β-carboline derivatives possessing potential bioactivity. Using electron-withdrawing protective groups, the substrate underwent a C2-selective annulation and afforded the structurally useful spiro-pseudoindoxyl found in natural indole alkaloids.3. We have developed a palladium catalyzed tandem reaction to construct poly substituted pyrroles through a Tsuji-Trost reaction/Hydroamination/1,3-H transfer process.4. Using a gold-catalyed tandem enyne cyclization/iminium cyclization reaction as key step, we have finished formal synthesis of indole alkaloids:Minfiensine. 5. We have also designed a gold catalyzed tandem enyne cyclization/F-C reaction to construct the structure core of indole alkaloids Phalarine. Although this key reaction has not come true, the related experience strengthened our understanding of the reactivity of indoles and gave useful clues to complete total synthesis of Phalarine.