Phospholones from Diacetylenic Ketones: Synthesis, Properties, and Reactivity

The reactivity of phosphanyl phosphonates toward diacetylenic ketones was studied. Reactions resulted in the selective formation of phospholones via phosphaalkene intermediates. Phospholones were obtained in yields of 37-96% depending on the substituent on the acetylenic unit. Reduction of the phenyl-substituted phospholone resulted in the formation of a persubstituted phosphole bearing a hydroxyl group in position 3 in 64% yield, and its oxidation led to oxaphospholone in 77% yield. Both of these modifications led to substantial changes in the optoelectronic properties of the compounds and bathochromic shifts of the longest wavelength absorption maximum.