Activation of boryl-, borylene and metalloborylene complexes by isonitrilesDedicated to Professor Dr F. Ekkehardt Hahn on the occasion of his 60th birthday.Electronic supplementary information (ESI) available: Expeirmental, computational and X-ray crystallographic studies details. CCDC 1060845-1060847. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5cc04712a

The reactions of isonitriles with a variety of metalloboryl and metalloborylene species are shown to yield a range of products, none of which display the typical Lewis acid-base reactivity previously observed between such metal complexes and other Lewis bases. Insertions of one, or several, isonitriles into the metal-boron bond give cyclic and spiro compounds with bonding controlled by the electron count at the metal and in the ring. One or several isonitriles can insert into metalloboryl and metalloborylene complexes to afford cyclic or spiro compounds with bonding controlled by the electron count at the metal and in the ring.