Reaction of silylallenes with triplet molecular oxygen

A facile formal ene reaction of trisubstituted silylallenes with triplet molecular oxygen involving the cleavage of a H-C(sp(2)) bond has been described. For this formal ene reaction, the silyl substituent was found to be critical to induce peroxide formation. DFT calculations clearly show the dramatic weakening of the allenic C(sp(2))-H bond by the -silyl group.