利用一價銠金屬催化芳基格任納試劑進行1,4-位移與具有高鏡相選擇性之去對稱化反應

Abstract

本論文研究主題為探討使用一價銠金屬以及雙膦配基(S)-L10a形成之催化劑，於溫度30 °C下，進行芳基格任亞試劑93分子內去對稱化反應。其經由銠金屬的1,4-轉移及β-烷氧基脫去反應生成掌性含末端烯類化合物94，有21個例子，其產率為10-99%，鏡像選擇性介於75%至99%。此外，本文藉3個氫氘標記實驗深入探討其反應機構。有別於大部分文獻探討銠金屬經1,4-轉移後形成之中間體再進行加成反應的應用，本篇為透過銠金屬催化劑1,4-轉移之特性進行分子內去對稱化反應，並首度達到銠金屬由芳基銠中間體轉移至烷基銠中間體並生成高產率及高鏡像選擇性之末端烯類化合物，在藥物及材料之合成開發有其運用性。This thesis aims to discuss an enantioselective intramolecular desymmetrization of aryl Grignard reagents. In the presence Rh(I)-catalyst, in situ generated from [RhCl(coe)2]2 and (S)-Segphos (S)-L10a, the Grignard reagents 93 are transformed into chiral compound 94, via 1,4-rhodium shift and beta-alkoxy elimination sequentially, in 10–99% yields and 79–99% ees. Additionally, a series of experiments of deuterium-labeling provide a mechanistic insight of this transformation.Apart from most of the studies, focusing on the addition reactions of intermediates formed by 1,4-rhodium shift, this one is the first example of demonstrating synthesis of chiral intramolecular desymmetrization directly after 1,4- rhodium shift. With the high chemical yields and high enantioselectivities of the desired terminal alkenes, the transformation offers its synthetic potentials in drug synthesis.