SELECTIVE chemical transformations involving hydrocarbons are a major
goal in synthetic chemistry. Transition-metal complexes are capable of
promoting a range of selective transformations of organic molecules u
nder mild conditions(1,2), and much effort has been devoted to studyin
g their reactivity towards hydrocarbons(3-7). Here we report a reactio
n promoted by a rhodium complex in which a methylene (CH2) group can b
e abstracted from a methyl (CH3) group and inserted into a variety of
bonds, such as Si-H, Si-Si and C-H. Our approach presently requires a
certain coordination geometry in the metal complex, involving chelatio
n of the metal centre, but we believe that it can be extended to other
substrates capable of metal coordination and may eventually lead to a
general strategy for CH2 transfer from hydrocarbons to other molecule
s under mild conditions.