Stiba‐, Arsa‐ and Phosphastannenes: Syntheses and Reactivities.

A facile synthesis for unprecedented stibastannene (10) featuring a Sn=Sb‐double bond together with the homologous arsa‐ (9) and phosphastannenes (8) is presented. Chloride abstraction from respective stannyl pnictinidenes [E=P (5), As (6), Sb (7)], which were made accessible by reduction of ECl3 addition products at an intramolecular phosphine‐stabilized stannylene, gave the pnictastannenes in moderate yields. The pnictastannenes coordinate Pd(PPh3)2 fragments (12–14) and the phosphastannene forms also a nickel coordination compound with the Ni(PPh3)2‐fragment (11). 2,3‐Dimethylbutadiene shows a [2+4]‐cycloaddition (15–17) in reaction with the pnictastannenes (8–10). Products of a [2+2]‐addition (18, 19) were isolated as the phosphaalkyne reaction products for 8 and 9. Addition of an O−H bond at the Sn=P‐bond was found in reaction of water with phosphastannene 8. Reaction with ammonia afforded the NH3‐adducts (21–23) at the tin atom for pnictastannenes 8–10. Only in the case of the arsastannene an azide reaction product featuring a three membered Sn−As−N‐ring was obtained. [ABSTRACT FROM AUTHOR]