Part 1: Origin Of Enantioselectivity In Iridium–catalyzed Asymmetric Hydrogenations Of Substituted Pyridinium Salts And Benzodioxines. Part 2: Reactivity Of Nickel(iii)-Intermediates In Reductive Elimination And Radical Dissociation. Part 3: Effects Of The Pyridinium Substitution On The C-N Bond Act