Reactivity of a Phosphanylcarbene (λ5‐Phosphaacetylene) with Lewis Acids: X‐Ray Crystal Structures of the First Carbene‐Gallane Complex and C‐Gallyl‐Substituted Phosphorus Ylide

A remarkably diverse reactivity toward Lewis acids is exhibited by the phosphanylcarbene (R2N)2PC̈SiMe3 (R  c-C6H11). The methylated Lewis acids MMe3 (M  Al, Ga, In) undergo 1,2 addition reactions to form the C-substituted phosphorylides 1 (X  Me), while the corresponding chlorides MCl3 form the first stable phosphanylcarbene–Lewis acid complexes 2 (X  Cl).