Novel Reactions of λ 5 ‐Phosphorins and Their Tricarbonylchromium Complexes

Cyclic phosphorus ylides such as (1) have been deprotonated for the first time; the “double” ylide (2) is formed which adds electrophiles E ⊕ (D ⊕ ,CH   3 ⊕ , PhCH   2 ⊕ ) with formation of (3) . In principle, the same reactions are possible with the more strongly “ylidie” (CO) 3 Cr‐complexes (4) .