Reaction mechanism of organoselenium-catalyzed syn-dichlorination of alkenes: a DFT study

A new method for the syn-dichlorination of alkenes at room temperature has been proposed by Denmark et al. The method uses diselenide (PhSeSePh) as the precatalyst, benzyltriethylammonium chloride (BnEt₃NCl) as the source of chlorine, and an N-fluoropyridinium salt as the oxidant to recover the catalyst. This approach has achieved exquisite diastereocontrol on a number of alkene substrates. In this paper, we report the results of DFT calculations we performed to study the mechanism of this reaction. We were able to identify a reasonable reaction path, including the intermediate and transition-state structures. The results also indicate that PhSeCl₃, rather than PhSeCl, is the active catalyst.

A simple and highly diasteroselective approach for the vicinal dichlorination of functional olefins

An efficient strategy for triphenylphosphine oxide-catalyzed vicinal dichlorination of functional olefins was developed using sulfuryl chloride as the source of chloride.