A radical path to 1,2-diphosphacyclobutenes.

Area of Science:

• Organometallic Chemistry
• Phosphorus Chemistry

Background:

• Di-tert-butyldiphosphatetrahedrane is a unique phosphorus cage compound.
• The synthesis of novel phosphorus heterocycles is of significant interest in synthetic chemistry.

Purpose of the Study:

• To explore the reactivity of di-tert-butyldiphosphatetrahedrane with electrophilic reagents.
• To synthesize and characterize new 1,2-diphosphacyclobutene derivatives.
• To achieve the synthesis of the elusive 1,2-dihydro-1,2-diphosphacyclobutene.

Main Methods:

• Reaction of di-tert-butyldiphosphatetrahedrane with Mes*O˙, (PhSe)₂, and I₂.
• Reduction of a resulting 1,2-diphosphacyclobutene derivative using LiAlH₄.

Main Results:

• Successful synthesis of 1,2-diphosphacyclobutene derivatives with R = OMes*, SePh, and I.
• Isolation and characterization of the previously elusive 1,2-dihydro-1,2-diphosphacyclobutene.

Conclusions:

• Di-tert-butyldiphosphatetrahedrane serves as a versatile precursor for 1,2-diphosphacyclobutene synthesis.
• The developed methods provide access to novel phosphorus-containing cyclic compounds.
• The synthesis of the dihydro derivative expands the scope of known diphosphacyclobutene structures.