Homogeneous transition metal catalysed hydroboration reactions are dis
cussed briefly, providing the background which led to the recent disco
very of metal catalysed diborations [additions of the B-B bond in B-2(
OR)(4) compounds] of alkynes, alkenes, 1,3-diynes, 1,3-dienes, and alp
ha,beta-unsaturated ketones. Catalysed additions of B-Si and B-Sn bond
s are also presented. Metal catalysed synthesis of organoboron compoun
ds is a useful new synthetic method.