Synthetic studies toward akuammiline alkaloids via a biomimetic pathway

학위논문 (석사)-- 서울대학교 대학원 : 자연과학대학 화학부, 2018. 8. 이홍근.In this chapter, initial synthetic strategy towards natural product rhazimal 2 via intermediate geissoschizine 1 is proposed, which involved Knoevenagel condensation, asymmetric 1,4 addition, and gold-catalyzed formal Pictet-Spengler cyclization. Synthetic efforts toward preparation of one of the key intermediate, α,β,γ-conjugated system 10 are demonstrated and major drawbacks of the sequence are highlighted. Alternatively, revised synthetic strategy is commenced. Its key features are represented as rigidity-dependent [3,3]-Ireland-Claisen type sigmatropic rearrangement to build direct C7-C16 bond, and later-stage functionalization to obtain unique (E)-ethylidene moiety.Abstract CHAPTER ONE. Synthetic Efforts toward Rhazimal 1. Introduction 2. Results and Discussion 2.1 Initial Synthetic Strategy and Synthetic Investigations towards Preparation of Aldehyde 9 2.2 Alternative Synthetic Pathway towards Aldehyde 9 and Preparation of α,β,γ-Unsaturated System 10 2.3. Alternative Synthetic Pathway towards Intermediate via Alkyne-Aldehyde Reductive coupling 2.4 . Examination in Rigidity Driven [3,3]-Ireland-Claisen Sigmatropic Rearrangement 2.5 Future Plan 3. Conclusion 4. Experimental Section 5. References 6. List of Abbreviations 7. 1 H and 13 C NMR Spectral DataMaste