FLP-type alkenylation of a phosphafluorene

Area of Science:

• Organophosphorus chemistry
• Materials science

Background:

• Phosphafluorenes, phosphorus-containing analogues of fluorenes, offer enhanced stability over traditional fluorene materials.
• Dibenzophospholes (DBPs) are a class of compounds that include phosphafluorenes.
• Phosphafluorene synthesis often involves reductive functionalization of terphenyl-based dihalophosphanes.

Purpose of the Study:

• To establish a high-yielding synthetic route for phosphafluorene 1.
• To explore various functionalization strategies for the synthesized phosphafluorene.
• To investigate the alkenylation of phosphafluorene 1 using frustrated Lewis pair (FLP) chemistry.

Main Methods:

• Synthesis of phosphafluorene 1 from ^DippTerPCl₂.
• Complexation of phosphafluorene 1 with AuCl, formation of its BH₃ adduct, and synthesis of its sulphide derivative.
• Alkenylation reaction using B(C₆F₅)₃ and phenylacetylene derivatives.

Main Results:

• A high-yielding route to phosphafluorene 1 was successfully developed.
• Various functionalized derivatives of phosphafluorene 1 were synthesized and characterized.
• Facile and E-selective alkenylation of phosphafluorene 1 was achieved via FLP catalysis, yielding zwitterionic phosphonium borates.

Conclusions:

• The developed synthetic methodology provides efficient access to phosphafluorenes.
• The study showcases the versatility of phosphafluorenes in coordination chemistry and FLP catalysis.
• The novel FLP-type alkenylation reaction expands the synthetic utility of phosphafluorenes.