Metal-Vinylidene-Catalyzed Oxidative Functionalization of Terminal Alkynes and Synthetic Studies toward (+)-Fendleridine

Abstract

Described in this dissertation are development and application of the catalysis mediated by transition metal vinylidene complexes. With a brief survey of oxidative functionalization of metal vinylidene species (Chapter 1), a mechanistically distinct approach toward oxygenative [2 + 2] cycloaddition of terminal alkynes with imines is discussed. It has been revealed that oxidative functionalization of terminal alkynes has a diverse mechanistic modalities depending on both metal complexes and oxidants employed. Through the studies, we have discovered diverse facets of the metal-vinylidene-catalyzed oxidative functionalization of terminal alkynes, in which terminal alkynes are converted to an array of acyl donors in practical and general senses (Chapter 2). Parallel with the effort in the new reaction discovery, an application of metal vinylidene catalysis has been pursued in the context of complex total synthesis. A cascade cyclization approach to (+)-fendleridine has been devised taking advantage of anti-Markovnikov selectivity in the metal-vinylidene-catalyzed cyclization of terminal alkynes. During the research, the oxidative indole acylation and relay-acyl-migration reactions were established. In addition, the feasibility of each cyclization event was briefly investigated. Details of the synthetic studies toward (+)-fendleridine are discussed in Chapter 3.

본 학위논문은 전이금속 비닐리덴 착물 촉매반응의 개발 및 응용에 대한 연구를 기술한다. 특유의 반응 기작을 지니는 금속 비닐리덴 화합물의 산화적 기능화에 대한 소개에 이어 (제 1장), 말단 알카인과 이민의 [2 + 2] 고리첨가반응에 대해 논의한다. 후속 연구를 통하여 말단알카인의 산화적 기능화 반응은 사용되는 금속 촉매와 산화제에 따라 다양한 양상을 보일 수 있음을 밝혀내었다 (제 2장). 새로운 촉매 반응의 개발과 함께, 금속 비닐리덴 반응을 활용한 전합성 연구가 진행되었다. 금속 비닐리덴의 안티-마르코브니코브 선택성을 이용하는 연쇄 고리화 접근법을 고안하여, (+)-펜들러리딘의 전합성 연구를 진행하였다. 제 3장에서는 (+)-펜들러리딘의 최초 거울상선택적 합성을 위한 연구를 소개하였다.