Synthesis of well-defined soluble polystyrene supports: Impact of polymer chain on grafted organotin reagent activity

The synthesis of well-defined soluble polystyrene supports bearing tin hydride functionalities has been achieved in two steps. First, a precursor was prepared by copolymerization of styrene and acetoxystyrene using atom transfer radical polymerization. Prior any modification, this precursor was fully characterized to check its structure. Then in a second part, tin hydride functions were introduced by a four step process. The chemical modification was monitored by IR and 1H NMR spectroscopies. The soluble support was also characterized by triple detection size exclusion chromatography at each step. Two families of supports were synthesized by varying the molecular weight and the degree of functionalization. The effectiveness of these tin hydride supports was tested through the reduction of 6-bromohexene and compared with the small counterpart Bu3SnH. Measurements of rate constant for hydrogen transfer were also reported.