Rhodium-catalyzed intramolecular cyclization for synthesizing thiodihydropyrans

Area of Science:

• Organic Chemistry
• Heterocyclic Chemistry

Background:

• Constructing multi-substituted dihydropyrans presents a significant synthetic challenge.
• Oxygen-containing heterocycles are vital structural motifs in many pharmaceuticals and natural products.

Purpose of the Study:

• To develop an efficient and general method for synthesizing multi-substituted dihydropyrans and related oxygen heterocycles.
• To explore the use of thiones and metal carbenes in intramolecular cyclization reactions.

Main Methods:

• Employing thiones and metal carbenes in reactions with xanthate and triazole derivatives.
• Utilizing intramolecular cyclization strategies to form dihydropyran and dihydrofuran cores.
• Investigating reaction conditions to prevent undesired 1,2-hydride migration.

Main Results:

• Achieved efficient synthesis of multi-substituted dihydropyrans and dihydrofurans.
• Successfully inhibited 1,2-hydride migration, leading to the formation of thiodihydropyrans.
• Obtained target compounds in excellent yields.

Conclusions:

• The developed method provides a robust route to complex oxygen-containing heterocycles.
• The proposed mechanism involves a rhodium-carbene intermediate, offering insights into the reaction pathway.
• This approach offers a valuable tool for synthetic chemists targeting diverse heterocyclic structures.