DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB2 Macromonomers

We describe here the first example of an iterative convergent strategy for the synthesis of dendritically branched polymers involving condensation coupling reactions of AB 2 macromonomers. The macromonomers were synthesized by living anionic polymerization, initiated with 3- tert -butyldimethylsiloxy-1-propyllithium and end capped with 1,1-bis(4- tert -butyldimethylsiloxyphenyl) ethylene. Following a deprotection reaction, the macromonomer, functionalized with two phenol groups and one primary alcohol group, can be built up into a dendritic structure by a series of Williamson coupling reactions and subsequent end group modification reactions. Since the dendri tic structures are built up from mac romonomers we have coined the term “DendriMac” to describe these branched polymers. In this paper, we will discuss the synthesis of the macromonomer, the iterative reaction sequence and merits of a convergent strategy. Some preliminary characterization data will also be reported.