Göttker-Schnetmann Inigo, Kenyon Philip, Mecking Stefan
Chair of Chemical Materials Science, Department of Chemistry, University of Konstanz, 78457, Konstanz, Germany.
Angew Chem Int Ed Engl. 2019 Dec 2;58(49):17777-17781. doi: 10.1002/anie.201909843. Epub 2019 Oct 24.
Functionalized aluminum alkyls enable effective coordinative chain transfer polymerization with selective chain initiation by the functionalized alkyl. (ω-Aminoalkyl)diisobutylaluminum reagents (12 examples studied) obtained by hydroalumination of α-amino-ω-enes with diisobutylaluminum hydride promote the stereoselective catalytic chain growth of butadiene on aluminum in the presence of Nd(versatate) , Cp* Nd(allyl), or Cp* Gd(allyl) precatalysts and [PhNMe H ]/[B(C F ) ]. Carbazolyl- and indolylaluminum reagents result in efficient molecular weight control and chain initiation by the aminoalkyl rather than the isobutyl substituent bound to aluminum. As confirmed for (3-(9H-carbazol-9-yl)propyl)-initiated polybutadiene (PBD), for example, by deuterium quenching studies, polymer chain transfer by β-hydride transfer is negligible in comparison to back-transfer to aluminum.
官能化烷基铝能够实现有效的配位链转移聚合，通过官能化烷基进行选择性链引发。用二异丁基氢化铝对α-氨基-ω-烯烃进行氢化铝化反应得到的（ω-氨基烷基）二异丁基铝试剂（研究了12个实例），在新癸酸钕、五甲基环戊二烯基钕（烯丙基）或五甲基环戊二烯基钆（烯丙基）预催化剂以及[PhNMe₂H][B(C₆F₅)₄]存在的情况下，促进丁二烯在铝上的立体选择性催化链增长。咔唑基铝试剂和吲哚基铝试剂能实现有效的分子量控制，且链引发是由与铝相连的氨基烷基而非异丁基取代基完成的。例如，通过氘淬灭研究证实，对于（3-（9H-咔唑-9-基）丙基）引发的聚丁二烯（PBD），与向铝的反向转移相比，通过β-氢化物转移进行的聚合物链转移可忽略不计。
