Photodecomposition of selenosulfonates and their facile photoaddition to alkenes 1

Phenyl areneselenosulfonates (1) are very photosensitive and easily undergo photodecomposition via initial homolysis of the SeS bond. In the presence alkenes this facile photodissociation of 1 can be used to initiate a free radical chain reaction (eq 6) that leads to addition of 1 to the alkene to form β-phenylselenosulfones (2). The photoaddition requires much shorter reaction times than the non-photolytic addition of 1 to alkenes described recently.2