Phosphine-Catalyzed Reactions Involving γ-Substituted Allenoates Or MBH Carbonates With Activated Dienes

Phosphine-mediated domino annulation reactions involving allenoates or MBH derivatives have constructed lots of useful carbon-and heterocycles. We have summarized the progress in phosphine-mediated reactions which allenoates were participated in detail in chapter one. Then we introduced active1,3-bis(sulfonyl)butadiene to the phosphine-mediated reactions which allenoates and MBH derivatives were involved on the basis of summarizing and analyzing the recent progress. As a result of the investigation, we have developed four kinds of new reactions and four novel types of compounds.(1) We have developed an efficient tris(4-chlorophenyl)phosphine-catalyzed domino benzannulation reaction between dienic sulfones and γ-CH3allenoates, which provided access to biaryls successfully. TLC monitoring analysis clearly showed that an key intermediate was formed during the reaction, which offered convincing evidence for the reaction mechanism. The two kinds of biaryl products were converted to the same compound under the same reduction conditions. In addition, the biaryl product was derivatized to the corresponding Suzuki, Heck, and Sonogashira products through transition-metal-catalyzed cross-coupling reactions.(2) During the optimization of the phosphine-catalyzed domino benzannulation reaction conditions to synthesize biaryls, an unexpected bicyclo[3.2.0]heptene was formed when the more nucleophilic tributylphosphine was used as the catalyst. Upon detailed optimization of the reaction conditions, we have presented trimethylphosphine-catalyzed domino sequential reactions in which dienic sulfones and γ-CH3allenoates can be converted into bicyclo[3.2.0]heptene derivatives in moderate to good yield in a short period of time. To our knowledge, γ-CH3allenoates acted as a new kind of1,2,3-C3synthons through a new reaction pattern for the first time. This protocol also represented an extremely simple and efficient way to prepare bicyclo[3.2.0]heptenes.(3) We replaced γ-CH3allenoates with MBH carbonates to further explore the reactions when the above-mentioned works were completed because MBH carbonates exhibited similar reactivities compared with allenoates in the phosphine-catalyzed reactions. Results showed that a highly efficient sequential annulation domino reaction between1,3-bis(sulfonyl) butadienes and MBH carbonates in the presence of tris(4-fluorophenyl)phosphine was developed to generate bicyclo[4.1.0]heptene compounds with excellent yields and high diastereoselectivities. Remarkably, aliphatic substituted diene gave gratified result as various aromatic substitutes. To our knowledge, it was the first example that MBH carbonates serve as a new kind of1,2,3-C3synthons in this reaction.(4) We proposed the corresponding reaction mechanism which explained the formation of the products well and predicted the relevant intermediates during the research of the above phosphine-catalyzed sequential annulation domino reaction to construct bicyclo[4.1.0]heptenes. At the same time, an unexpected small amount of cycloheptatriene was formed in toluene when we optimized the reaction conditions. After detailed optimization of the reaction conditions, we have achieved cycloheptatriene derivatives through tris(4-fluorophenyl)phosphine-catalyzed intermolecular [4+3] cycloaddition from1,3-bis(sulfonyl) butadienes and MBH carbonates in toluene. Strong electron-withdrawing groups gave better yields than that of electron-donating groups of dienes. Moreover, we can only obtain the seven-membered carbocycles effectively in non-polar solvent such as toluene, xylene and mesitylene.