Study On Pd-catalyzed Tandem Reactions Of Aryl Halides And Propargyl Furylmethyl Ethers

Cascade reactions are capable of synthesizing novel and complex molecules from readily available starting materials in an efficient and economic manner. This type of reaction constitutes a fascinating branch of organic chemistry and can be considered to fall under the banner of green chemistry. In particular, transition-metal-catalyzed processes have blossomed into extraordinarily powerful tools for carbon-carbon bonds and carbon-heteroatom bonds formation by employing only catalytic amounts of mediators. Chemistry in this field has been developed rapidly in past decades.Great efforts have been made on the palladium-catalyzed cascade reactions via allene intermediates in our group, providing efficient ways to rapid synthesis of structurally diverse polycyclic molecules. Based on these studies, my thesis focuses its attention on a novel sequential palladium-catalyzed transformation of aromatic halides and propargylic2-furylmethyl ethers via allenyl furylmethyl ether intermediates. The cascade process involved coupling, propargyl-allenyl isomerization, intramolecular [4+2] cycloaddition and bridged oxa-ring opening, affording functionalized dihydroisobenzofurans under mild reaction conditions with respectable yields and diastereoselectivities. The key step of this process was the base-promoted propargyl-allenyl isomerisation while the stereoselectivity of this process was determined by Diels-Alder reaction.