SmI2-H2O-mediated 5-exo/6-exo lactone radical cyclisation cascades.

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Radical cyclizations are powerful tools for constructing complex molecular architectures.
• Lactone functional groups present unique challenges in radical cascade reactions.
• Developing efficient methods for creating bicyclic systems is crucial in drug discovery and materials science.

Purpose of the Study:

• To develop a novel synthetic strategy for constructing carbo[5.4.0]bicyclic motifs.
• To investigate the utility of samarium diiodide (SmI2)-water reagent system in mediating complex cyclizations.
• To achieve diastereoselective synthesis of bicyclic compounds in a one-pot procedure.

Main Methods:

• Employing the SmI2-H2O reagent system for radical generation.
• Initiating 5-exo and 6-exo lactone radical cascade cyclizations.
• Utilizing a one-pot reaction strategy to form multiple bonds and rings sequentially.

Main Results:

• Successful mediation of challenging lactone radical cascade cyclizations.
• Formation of carbo[5.4.0]bicyclic motifs with high efficiency.
• Establishment of two new carbocyclic rings and four stereocenters in a diastereoselective manner.

Conclusions:

• The SmI2-H2O reagent system is highly effective for complex lactone radical cyclizations.
• This method provides a diastereoselective, one-pot route to valuable carbo[5.4.0]bicyclic scaffolds.
• The developed strategy offers a significant advancement in the synthesis of intricate carbocyclic frameworks.