Novel generation of selenoaldehydes through stannic chloride-induced unsymmetrical C–Se bond cleavage of bis(N,N-dimethylcarbamoylseleno)methanes

Treatment of a benzene or a CH2Cl2 solution of bis(N,N-dimethylcarbamoylseleno)methanes with SnCl4 afforded β-1,3,5-triselenanes, and the key intermediates, acylselonium ions and selenoaldehydes, were successfully trapped by using allyltrimethylsilane or 2,3-dimethyl-1,3-butadiene to obtain the allylation products or the cycloadducts, respectively.