Efficient intermolecular [2 + 2 + 2] alkyne cyclotrimerization in aqueous medium using a ruthenium(IV) precatalyst

Area of Science:

• Organometallic Chemistry
• Catalysis
• Green Chemistry

Background:

• The [2 + 2 + 2] cyclization is a vital reaction for synthesizing substituted aromatic compounds.
• Developing efficient and environmentally friendly catalysts for this transformation is a key research area.

Purpose of the Study:

• To investigate the catalytic activity of a dimeric bis(allyl)-ruthenium(IV) complex in the [2 + 2 + 2] cyclization reaction.
• To explore the use of an aqueous medium for this important organic transformation.

Main Methods:

• Synthesis and characterization of the dimeric bis(allyl)-ruthenium(IV) complex [{Ru(eta3:eta3-C10H16)(mu-Cl)Cl}2].
• Evaluation of the complex's catalytic performance in the [2 + 2 + 2] cyclization of various terminal and internal alkynes.
• Reaction optimization in an aqueous medium.

Main Results:

• The dimeric bis(allyl)-ruthenium(IV) complex demonstrated high catalytic efficiency for the [2 + 2 + 2] cyclization.
• The reaction proceeded effectively in an aqueous medium, highlighting the complex's stability and activity in water.
• A range of terminal and internal alkynes were successfully cyclized, producing diverse aromatic products.

Conclusions:

• The dimeric bis(allyl)-ruthenium(IV) complex is a highly effective catalyst for the [2 + 2 + 2] alkyne cyclization.
• The development of this catalytic system in aqueous media represents a significant advancement in green synthetic chemistry.