A catalytically active aluminum-based system for Diels-Alder transformations is reported. The system was generated by mixing a β-diketiminate-stabilized aluminum bistriflate compound with Na[BAr(Cl) 4 (Ar(Cl) =3,5-Cl2 C6 H3). Solid-state analysis of the catalytic system reveals a unique structure incorporating a two-dimensional coordination polymer. According to the experimental results obtained from several Diels-Alder transformations, the aluminum-based system appears to be a more practical and more robust alternative to the recently reported compounds based on carbon and silicon cations.

is a free-radical anion of the reactive oxygen species (ROS) family. In the present study, the relative reactivities of 14 structurally varied aliphatic alcohols toward electrochemically generated O 2 * À were investigated in solutions of N,Ndimethylformamide by using cyclic voltammetry (CV). Upon the stepwise addition of each substrate, the chemical reversibility of the one-electron voltammetric reduction of the dioxygen (O 2 ) to O 2 * À was found to decrease, which enabled the extent of radical inhibition to be determined by measuring the resultant oxidative peak current (I pa ) magnitudes on the reverse scan of the CV. Based on the electrochemical responses gathered, best fit plots of the percentage decrease in the anodic peak current (%DI pa ) against the concentration of substrate added were obtained and compared according to the different classes of alcohols that were examined (linear, fluorinated, branched, and poly-hydroxylated). In addition, different parameters, such as electronic effects, steric effects, degree of hydroxylation, and kinetic effects that affect the O 2 * À scavenging abilities of the alcohols, are also discussed.

Firstly, I would like to thank Nanyang Technological University (NTU) for awarding me with a Research Scholarship and for their financial support to attend an overseas conference.My utmost gratitude also extends to my supervisor, Prof. Richard D. Webster, for his continuous support and guidance throughout my graduate studies and during the preparation of this thesis.My PhD was definitely also made an extremely enriching experience because of the countless opportunities provided by Prof. Webster to explore and learn many new and interesting concepts within the field of electrochemistry.I would like to acknowledge my previous mentor, Prof. M. Senthilkumar, for bringing so much fun and laughter during my undergraduate days, and for giving his invaluable advice and encouragement to pursue a PhD.My sincere appreciation is also conveyed to Dr. S. A. Pullarkat and Prof. D. Vidovic for imparting to me essential laboratory skills when I was an undergraduate student, and at the same time introducing me to the world of scientific research which also piqued my interest in it.Many thanks to my fellow lab mates

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In Ta ble 1, entries 5-7 of this Communication,the chemical structures of three products 12, 22,and 23 were printed in out of order.The correct structures andorder are listed here. The authors apologize for this oversight.Table1.L Al(OTf) 2 /Na[BAr Cl 4 ]-and tBuCl/AgOTf( HBA)-catalyzed Diels-Alder reactionso fd ienophile 4 with 2,3-dimethyl-1,3-butadiene( 1), 2methyl-1,3-butadiene (18), or cyclohexadiene ( 19). The results are listed as:t ime (h), yield (%), trans/cis or endo/exo,a nd para/meta ratios for each run. Entry Diene Dienophile AdductLAl (OTf) 2 /Na[BAr Cl 4 ]H BA 5 12 h2 4h 93 %5 8% 99:1 99:1 --6 12 h [a] 10 h 97 %53 % 99:1 99:1 > 99 %97 % 7 7h [b] 24 h 94 %25 % 99:1 99:1 --[a] 10 %C atalyst loading. [b] 15 %C atalystloading.