Synthesen, Struktur und Eigenschaften von 1,2,5‐Phosphadiborolanen

Syntheses, Structure and Properties of 1,2,5‐Phosphadiborolanes Reactions of ( Z )‐1,2‐bis[chloro(diisopropylamino)boryl]ethane with Li 2 PC 6 H 5 and of 1,2‐bis[chloro(diisopropylamino)boryl]‐1,2‐diisopropylideneethane with [LiPh 2 ·dme] yield the 1,2,5‐phosphadiborolanes 1 and 2 , respectively. The compounds are characterized by 1 H‐, 11 B‐, 13 C‐, and 31 P‐NMR spectroscopy as well as an X‐ray structure analysis of 2 . Low‐temperature 1 H‐NMR studies show that the inversion barrier at P is distinctly lower than that of related unsaturated compounds. This might be the result of a favorable BP‐π interaction in the transition state of the inversion at the phosphorus atom. Reaction of 1 with S 8 or CS 2 leads to the 1,2,5‐thiadiborolane 3 .