Efficient Two-Step Synthesis of 11,11'-Dithiobis[1-(2-bromo-2-methylpropionyloxy)undecane], a Conventional Initiator for Grafting Polymer Brushes from Gold Surfaces via ATRP

11,11'-Dithiobis[1-(2-bromo-2-methylpropionyloxy)undecane], a conventional initiator for grafting polymers from gold surfaces, was synthesized in two steps from 11-mercapto-1-undecanol in 88-92% overall yield. Oxidative dimerization of 11-mercapto-1-undecanol with a catalytic amt. of sodium iodide and 30% hydrogen peroxide in Et acetate proceeded in 96% yield. Esterification with 2-bromoisobutyryl bromide in dichloromethane was clean and almost quant. (92% yield) with pyridine used as base, whereas triethylamine gave a messy reaction (64% yield). Alternatively, esterification with 2-bromo-2-methyl-propanoic acid in dichloromethane occurred readily under Steglich's conditions with N,N'-dicyclohexylcarbodiimide (DCC) and a catalytic amt. of dimethylaminopyridine (DMAP; 88% yield). [on SciFinder(R)]