Rhodium-catalyzed linear codimerization and cycloaddition of ketenes with alkynes

Area of Science:

• Organometallic Chemistry
• Organic Synthesis
• Catalysis

Background:

• Ketenes are versatile synthetic intermediates.
• Rhodium catalysts are effective for various organic transformations.
• Efficient synthesis of dienones and furans remains an area of interest.

Purpose of the Study:

• To develop novel rhodium-catalyzed reactions involving ketenes and alkynes.
• To synthesize dienones via linear codimerization.
• To synthesize furans via cycloaddition.

Main Methods:

• Utilized a rhodium catalyst, RhCl(PPh(3))(3).
• Investigated the reaction of alkyl phenyl ketenes with internal alkynes.
• Investigated the reaction of diaryl ketenes with internal alkynes.

Main Results:

• Successfully developed a novel rhodium-catalyzed linear codimerization of alkyl phenyl ketenes with internal alkynes, yielding dienones.
• Developed a novel synthesis of furans through an unusual cycloaddition of diaryl ketenes with internal alkynes.
• Both reactions proceeded smoothly with the same rhodium catalyst.

Conclusions:

• The developed synthetic methods offer efficient routes to dienones and furans.
• Reaction outcomes are highly dependent on the structure and reactivity of the starting ketenes.
• The rhodium catalyst, RhCl(PPh(3))(3), is effective for both transformations.