- 學位論文
鈀催化內在炔類的加成反應之探討
Palladium-Catalyzed Addition Reactions of Internal Alkynes
摘要
近幾年來，鈀金屬錯合物是提供生成碳-碳鍵最實用及有效的方法之一。本篇論文主要是探討鈀金屬錯合物催化炔類的加成及氧化反應。第一部份是利用2-炔基苯甲醛 (2-alkynylbenzadehydes) 和芳香基碘化物，以甲醇為溶劑，在零價鈀 (Pd(PPh3)4) 和碳酸鉀 (K2CO3)的存在下，加熱迴流24小時，進行酯化-氫芳香基化反應 (esterification -hydroarylation)，可得到氧化-加成產物甲基2-(2,2-二取代乙烯基)苯甲酯 (methyl 2-(2,2-disubstitutedvinyl)benzoates)，產率為35-74 % 及五員環環化產物3-甲氧基-1-單取代亞甲基-3-氫異苯并呋喃(3-methoxy-1-monosubstitutedmethylene-3-hydroisobenzofurans)，產率為3-18 %。 第二部份是以甲醇為溶劑，在二價醋酸鈀 (Pd(OAc)2)、三苯磷 (PPh3) 和甲醇鈉的存在下，反應48小時，可以成功地將內在炔類 (internal alkynes) 還原成烯類 (37- 50 %) 或烷類 (57- 92 %)。在相同的條件下，將溶劑甲醇改為四氫呋喃 (THF)，此時內在炔類只會被還原成烯類 (61-80 %)。上述還原反應步驟是經由先生成甲氧根鈀金屬中間物(palladium methanolate)，接著再進行β-氫脫去反應 (β-hydride elimination) 及還原脫去反應 (reductive elimination) 而得到還原產物。
並列摘要
Palladium offers one of the most versatile and efficient tools for the formation of carbon-carbon bond in recent years. In this thesis, we describe the palladium-catalyzed addition reactions of internal alkynes. Firstly, treatment of 2-alkynylbenzaldehydes with aryl iodides in the presence of Pd(PPh3)4 and K2CO3 in refluxing methanol for 24 hours gave the dehydrogenation-addition products, methyl 2-(2,2-disubstituted vinyl)benzoates in 35-74 % yields ; together with the cyclization products, 3-methoxy-1-monosubstitutedmethylene-3-hydroisobenzofurans in 3-18 % yields. Secondly, the reaction of internal alkynes with sodium methoxide in the presence of Pd(OAc)2 and PPh3 in methanol for 48 hours gave the reduction products, alkenes (37-50 %) or alkanes (57-92 %) . However, the reaction of internal alkynes were carried out under the same reaction condition except in THF, only alkenes (61-80 %) was obtained. This reaction proceeds through a palladium methanolate complex, followed by β-hydride elimination and reductive elimination.