Dilithium diamides of Me3Si- and i-Pr3Si-protection were examined as difunctional initiators for polymerization of methyl methacrylate (MMA) in toluene in combination with tributylaluminum. The less sterically demanding Me3Si-derivative underwent 1,2-addition (carbonyl addition) in the initial stage of polymerization to form type B poly(MMA) (PMMA) as a minor component (26%). The i-Pr3Si-derivative gave type A PMMA exclusively with the 1,3-xylylenediamine unit in the middle of the chain. H2/Pd-C-mediated cleavage of the diamine unit yielded PMMA with a half molar mass and narrow molar-mass distribution.
- Takehiro Kitaura
- Tatsuki Kitayama
