Borataalkenes, boraalkenes, and the η 2 -B,C coordination mode in coordination chemistry and catalysis

Borataalkenes are the boron-containing isoelectronic analogues of alkenes. Compared with alkenes, the borataalkene ligand motif in transition metal coordination chemistry is relatively underexplored. In this tutorial review, the synthesis of borataalkene complexes and other transition metal complexes featuring the η2-B,C coordination mode are described. The diversity of coordination modes and geometry in boraatalkene complexes, and the spectroscopic and structural evidence supporting their assignents are highlighted. The applications of the borataalkene ligand motif in homogeneous catalysis, especially those involving 1,4-azaborines, is discussed. Finally, the use of borataalkene complexes as reactive intermediates in catalysis, usually derived from geminal diboron compounds is summarized.