Parts of this thesis have been published in: ; Supervisor's Foreword; Abstract; Contents; Abbreviations, Acronyms and Symbols; 1 Introduction; 1.1 Introduction; 1.2 Importance of Nitrogen-Substituted Four, Five and Six-Membered Rings; 1.2.1 Four-Membered Rings; 1.2.2 Five-Membered Rings; 1.2.3 Six-Membered Rings; 1.3 Cyclopropanes and Cyclobutanes: General Structure and Reactivity; 1.3.1 Cyclopropanes; 1.3.2 Cyclobutanes; 1.4 Donor-Acceptor Substituted Cycloalkanes; 1.4.1 Structure and Reactivity; 1.4.2 Formal Cycloaddition versus Annulation

1.4.3 Synthesis and Reactivity of Donor-Acceptor Substituted Cyclopropanes1.4.3.1 Synthesis of Donor-Acceptor Substituted Cyclopropanes; 1.4.3.2 Friedel-Crafts Alkylation; 1.4.3.3 Lewis Acid Mediated [3 + 2] Annulation of Olefins and Alkynes; 1.4.3.4 Lewis Acid Mediated [3 + 2] Annulation of Carbonyl Compounds; 1.4.3.5 Lewis Acid Mediated [3 + 2] Annulations with Other Dipolarophiles; 1.4.3.6 [3 + 2] Annulations with Other Modes of Activation; 1.4.3.7 Enantioselective Processes Involving DA Cyclopropanes; 1.4.4 Conclusion; 1.4.5 Donor-Acceptor Substituted Cyclobutanes; 1.4.5.1 Synthesis

1.4.5.2 [4 + 2] Annulations1.4.6 Conclusion; 1.5 Reactivity of Nitrogen-Substituted Small Cycloalkanes; 1.5.1 Cyclopropanes; 1.5.2 Cyclobutanes; 1.5.3 Conclusion; 1.6 Work in the Group; 1.7 Goal of the Project; References; 2 Ring-Opening Reactions of Aminocyclopropanes; 2.1 [3 + 2] Annulation with Enol Ethers [1]; 2.1.1 Discovery of the Reaction and Optimization; 2.1.2 Scope and Limitations; 2.1.3 Mechanism; 2.1.4 Product Modifications; 2.2 [3 + 2] Annulation with Aldehydes; 2.3 [3 + 2] Annulation with Ketones; 2.4 Friedel-Craft Alkylation of Indoles [15]; 2.4.1 Preliminary Results

2.4.2 Synthesis of New Cyclopropane Analogues2.4.3 Optimization of the Reaction; 2.4.4 Scope of the Reaction; 2.4.5 Product Transformations; 2.5 Dynamic Kinetic Asymmetric [3 + 2] Annulation of DA Aminocyclopropanes; 2.5.1 DyKAT: 1st Generation; 2.5.2 DyKAT: 2nd Generation; 2.5.3 DyKAT: 3rd Generation; 2.5.4 Scope of the Reaction; 2.5.5 Origin of Asymmetric Induction; 2.6 Conclusion; References; 3 Synthesis and [4 + 2] Annulation of Aminocyclobutanes; 3.1 Discovery of the [2 + 2] Cycloaddition; 3.1.1 Synthesis of Methylidene Malonates

3.1.2 Discovery and Optimization of the [2 + 2] Cycloaddition3.2 Scope and Limitations; 3.2.1 Synthesis of Alkylidene Malonates; 3.2.2 Synthesis of Enimides; 3.2.3 Scope of the Reaction; 3.2.4 Product Modification; 3.3 [4 + 2] Annulation of Aminocyclobutanes; 3.3.1 Optimization of the Reaction; 3.3.2 Synthesis of Substrates; 3.3.3 Scope and Limitations; 3.4 Conclusion; References; 4 Conclusions and Outlook; References; 5 Experimental Part; 5.1 General Methods; 5.2 [3 + 2] Annulation with Enols Ethers; 5.3 [3 + 2] Annulation with Aldehydes; 5.4 [3 + 2] Annulation with Ketones