可見光光氧化還原催化反應於有機合成之應用研究(I) 利用可見光光氧化還原催化反應於有機合成是目前極為熱門之研究課題。由於大部份之有機化合物皆不吸收可見光，因此利用可見光催化有機反應產生之副反應相對較少。在本年度的計劃中，我們將以Ru(bpy)3Cl2 當做光氧化還原催化劑，用以合成兩個潛在之光致變色材料及一個潛在之熱致變色材料，並進一步探討其光致變色及熱致變色性質。其次，我們亦將設計、合成一潛在之有機光氧化還原催化劑，用以取代毒性高且來源有限之Ru(bpy)3Cl2 complex。研究重點則放在以下三個子題：（A） 應用可見光光氧化還原催化反應原理設計並合成新型潛在光致變色材料1。（B） 應用可見光光氧化還原催化反應合成新型潛在熱致變色材料2。（C） 設計並合成潛在有機光氧化還原催化劑3。這些有機衍生物之合成及鑑定，將有助於新型光致變色材料及熱致變色材料之研發，未來亦可應用於各類化學工業，如光學記憶體及光學開關等等。其次，如果成功，我們將可用有機光氧化還原催化劑取代毒性高且來源有限之Ru(bpy)3Cl2 complex 來進行有機化學反應。自2008 年起，利用可見光配合過渡金屬催化劑進行光氧化還原催化反應已廣泛被報導。由於Ru(bpy)3Cl2 complex 具有極佳之光物理性質，有機反應可以在包括家用燈泡、LED 燈、日光等任何可見光源下進行。因此，應用可見光光氧化還原催化反應於有機化學合成不但可節省能源且對環境非常友善，可謂相當符合「綠色/永續化學」的精神。有鑑於此，在本年度的計劃中，我們將焦點置於利用可見光光氧化還原催化反應於三種雜環化合物之合成，重點則放在以下三個子題：（A） 應用可見光光氧化還原催化反應於spirolactones 1 及2 之合成。（B） 應用可見光光氧化還原催化反應於2H-indazole 3 及quinazoline 4 之合成。（C） 應用可見光光氧化還原催化反應於benzo[d][1,3]oxazine 5 之合成。 Application of visible light photoredox catalysis in organic synthesis (I) The use of visible light sensitization as a means to initiate organic reactions is attractive due to the lack of visible light absorbance by organic compounds, reducing side reactions often associated with photochemical reactions conducted with high energy UV light. In this proposal, we will use Ru(bpy)3Cl2 as the photoredox catalyst in design, synthesis and characterization of two novel heterocyclic compounds and subsequently explore their potential photochromic and thermochromic properties. Furthermore, a rationally designed potential organic photoredox catalyst to replace Ru(bpy)3Cl2 is proposed. (A) Apply the visible light photoredox catalysis mechanism in design and synthesis of potential photochromic colorant 1,3-oxazine 1. (B) Use the visible light photoredox catalysis in synthesis of potential thermochromic dye spiropyran 2. (C) Rational design and synthesis of potential organic photoredox catalyst 3. The results of our studies may have the potential to provide practical applications of organic photochromes and thermochromes in photonic devices such as erasable memory media and optical switching. Moreover, if successful, we believe the high cost and potential toxicity of the ruthenium salts based photoredox catalyst can be replaced with the relatively inexpensive and less toxic organic photoredox catalyst for synthetic organic transformations. Application of visible light photoredox catalysis in organic synthesis (II) The use of visible light mediated metal polypyridyl photocatalysts in synthetic organic transformations has attracted much attention since 2008. Given the remarkable photophysical properties of the Ru(bpy)3Cl2 complex, organic reactions can be conducted using almost any source of visible light, including both store-bought fluorescent light bulbs and ambient sunlight. Therefore, transition metal photocatalysis represents a promising strategy towards the development of practical, scalable industrial processes with great environmental benefits. In this second year proposal, we will focus our attentions toward the synthesis of three classes of organic compounds using visible light photoredox catalysis catalyzed by Ru(bpy)3Cl2 complex. The three main topics to be explored are as following: (A) Synthesis of the spirolactones 1 and 2 via visible light photoredox catalysis. (B) Synthesis of the 2H-indazole 3 and quinazoline 4 via visible light photoredox catalysis. (C) Synthesis of the benzo[d][1,3]oxazine 5 via visible light photoredox catalysis.
