Reductive Denitrogenation of Six-membered Cyclic Nitronates to Densely Substituted Dihydrofurans with Raney & REG; Nickel/AcOH System

A protocol for the synthesis of 2,3-dihydrofurans by reductive denitrogenation/ring contraction of 6-membered cyclic nitronates was developed. The process utilizes cheap Raney & REG; nickel both as catalyst and stoichiometric agent without the need for high-pressure equipment. The products are formed in high purity and column chromatography is often not required. Studies on the substrate scope, functional group tolerance, and mechanism were performed. The developed approach provides a straightforward two-step access to densely substituted 2,3-dihydrofurans from nitrostyrenes and alkenes.

Automated summary

A protocol was developed for the synthesis of 2,3-dihydrofurans by reductive denitrogenation/ring contraction of cyclic nitronates. Cheap Raney nickel was used as both catalyst and stoichiometric agent, eliminating the need for high-pressure equipment. The products were obtained in high purity and often didn't require column chromatography. Studies on substrate scope, functional group tolerance, and mechanism were conducted. This approach provides a straightforward two-step access to densely substituted 2,3-dihydrofurans from nitrostyrenes and alkenes.