1,3-Dipolar Cycloaddition of Benzofuranone Derivatives and Azomethine Ylides Promoted by Simple Functional Ionic Liquids: Direct Access to Highly Substituted Pyrrolidine and Spirocyclic Benzofuranone

摘要

abstract_textpWe have successfully established an efficient catalytic system, which was effective for construction of both spiropyrrolidinebenzofuran-3-one and spiropyrrolidine-benzofuran-2-one compounds. The first 1,3-dipolar cycloaddition of 2-alkylidenebenzofuran-3-one with azomethine ylides with simple functional ionic liquids as catalysts was developed, affording a variety of spiropyrrolidine-benzofuran-3-one compounds containing highly substituted pyrrolidine motifs with a spiro quaternary stereogenic center in excellent yields (73-99 ). The highly efficient catalytic system exhibited broad substrate scopes under mild conditions. Meanwhile, this catalytic system was also extended to the cycloaddition of 3-alkylidene-benzofuran-2-one with azomethine ylides and gave spiropyrrolidinebenzofuran-2-one compounds in high yields (82-99) and 1,dipolar cycloaddition of 2-alkylidene-benzofuran-3-one with pyrazolidinone-based dipoles giving the desired products in 25-85 yields./p/abstract_text