Stereoselective Synthesis of Highly Substituted Δ~1-Pyrrolines: exo-Selective 1, 3-Dipolar Cycloaddition Reactions with Azlactones

摘要

We have developed a diastereoselective and efficient synthesis of highly substituted Δ~1-pyrroline-5-carboxylic acid scaffolds via a silver(Ⅰ)-catalyzed [3 + 2] cycloaddition reaction. The exo selectivity complements the endo-selective cycloaddition of related acyclic azomethine ylides very well. Diastereocontrol can be extended to the three stereogenic centers by appropriate choice of substrates and isolation conditions.