Synthesis of Medium-Sized Cycloalkenes via Fused-Cyclobutenes (Springer Theses)

This book explains the existence of the intermediate using two approaches: computational chemistry and coordination chemistry. In this book, the author has developed new methods for synthesizing medium-sized cycloalkenes by utilizing the 4π-electrocyclic reaction of fused-cyclobutenes. The fundamental and most important strategy and feature of the work are as follows: first, cyclobutene is used as a readily available raw material with high-strain energy to generate more strained medium-sized cis,trans-cycloalkadiene molecules. Second, by judiciously selecting the reaction conditions, the short-lived intermediate (medium-sized cis,trans-cycloalkadiene) can be converted to medium-sized cis- or trans-cycloalkenes. For the former, the generation of the medium-sized cis,trans-cycloalkadiene intermediate is greatly affected by the substituent on the cyclobutene, and there are few examples of its generation confirmed at room temperature. Regarding the latter, the synthesis of trans-cycloalkenes is noteworthy in terms of establishing a new synthetic methodology and providing one of the few asymmetric synthesis methods, which has not been achieved before. Readers of this book can gain novel insights into strained molecules involved not only in small-sized cycloalkenes but also in medium-sized ones. Cover Springer Theses Series Synthesis of Medium-Sized Cycloalkenes via Fused-Cyclobutenes Copyright Supervisor’s Foreword Acknowledgements Publications Contents 1. Introduction 1.1 Molecular Strain 1.1.1 Strain of Cycloalkanes 1.1.2 Strained Cycloalkanes 1.2 Background of This Thesis 1.2.1 Strain of Cycloalkenes 1.2.2 Cyclobutenes 1.2.3 Cyclobutenes as Synthetic Elements 1.3 Medium-Sized Trans-Cycloalkenes 1.3.1 Synthetic Methods for Trans-Cycloalkenes 1.3.2 Chemistry of Trans-Cycloalkenes 1.4 Our Previous Work References 2. Synthesis of Functionalized Medium-Sized Trans-Cycloalkenes by 4π-Electrocyclic Ring-Opening—Alkylation Cascade References 3. Synthesis of γ-Aryl Medium-Sized Cyclic Enones by 4π-Electrocyclic Ring-Opening—Heck–Matsuda Arylation Cascade References 4. Asymmetric Organocatalytic [2 + 2] Cycloaddition Affording Bicyclo[n.2.0]alkenes References 5. Conclusion 6. Experiments 6.1 Experimental Section for Chap. 2 6.1.1 General 6.1.2 A General Procedure for the Synthesis of Silyl Enol Ethers 6.1.3 A General Procedure for the Synthesis of Cyclobutenes 6.1.4 Procedures for the Synthesis of 1d, 1e, and 5i 6.1.5 Screening of Optimal Conditions 6.1.6 A General Procedure for the Synthesis of Trans-Cycloalkenes 6.1.7 Modified Procedures for the Synthesis of Trans-Cycloalkenes 6.1.8 Chirality Transfer 6.1.9 Synthetic Applications of MtCAs 6.1.10 Transformation of Ketones into Hydrazones for Structural Determination 6.1.11 Structural Determination of 2ca, 2fa, and 2fa′ 6.1.12 Supplemental Information 6.2 Experimental Section for Chap. 3 6.2.1 General Remarks 6.2.2 Experimental Details: Synthesis 6.2.3 Experimental Details: DFT Calculation 6.2.4 Supplemental Information 6.2.5 Reductive Elimination from Intermediate E 6.3 Experimental Section for Chap. 4 6.3.1 General 6.3.2 General Procedures 6.3.3 General Procedure for an Organocatalytic Asymmetric [2 + 2] Cycloaddition References