Catalytic enantioselective reactions of ortho quinone methides with chiral oxazaborolidinium ion catalysts

Kim, Seungtae Sungkyunkwan university 2021 국내박사

ortho-Quinone methides (o-QMs) display a cyclohexadiene core structure with an exocyclic methylene and a carbonyl group, which positioned by ortho to each other. It has attracted great scientific interests in recent decades due to the high reactivity and used as important intermediates in organic synthesis, enabling the straightforward installation of diverse aromatic molecules with successful applications to a number of complex natural products. Tandem reaction become a popular strategy which consists of at least two successive reactions. Tandem reaction could allow establishment of molecular complexity from simple precursors by combining several sequential formation of bonds in a single operation. The use of tandem reactions usually has increased rapidly in the area of chiral building blocks, pharmaceutical, and total synthesis. In this thesis, chiral oxazaborolidinium ion (COBI) catalyzed enantioselective reactions with ortho-quinone methides were studied. The first reaction introduced in this thesis is stereoselective synthesis of 2-aryl-2,3-dihydrobenzofuran from ortho-quinone methides and α-diazoester through tandem cyclopropanation/intramolecular rearrangement. Chiral 2-aryl-2,3-dihydrobenzofuran derivatives represent the building block of numerous bioactive compounds. In the presence of chiral oxazaborolidinium ion (COBI) catalysts, diverse 2-aryl-2,3-dihydrobenzofuran derivatives containing successive chiral centers including a quaternary center were obtained with excellent yields and stereoselectivities. Next, chiral oxazaborolidinium ion (COBI) catalyzed enantioselective cyclopropanation/homodienyl [1,5]-hydrogen shift using ortho-quinone methides and α-alkyl-α-diazoesters was developed to provide highly functionalized Rauhut-Currier products in high yield with excellent stereoselectivities. The synthetic functionality was showed by transformation to various coumarin derivatives and other Rauhut-Currier products. Finally, highly enantioselective Friedel-Crafts reaction of furan with ortho-quinone methides was successfully developed. Chiral triarylmethane derivatives applicated to various area such as dye, pH indicator, biological materials and so on. In the presence of chiral oxazaborolidinium ion catalyst, triarylmethane compounds were synthesized with excellent yields and enantioselectivity. 오쏘-퀴논 메타이드는 사이클로헥사다이엔 구조를 중심으로 하고 고리 밖 메틸렌 그룹과 카보닐 그룹이 오쏘 방향으로 위치한 화합물을 말한다. 최근 수 십년 간 오쏘-퀴논 메타이드는 높은 반응성 때문에 많은 과학자로부터 흥미를 불러일으켰다. 또한, 오쏘-퀴논 메타이드는 다양한 방향족 분자를 쉽게 붙임으로써 유기합성에 중요한 중간체로 이용되며 많은 복잡한 천연물에 성공적으로 적용되었다. 연속 반응은 두 개이상의 연속적인 반응으로 구성된 한 개의 반응으로, 여러 개의 분자간 결합이 순차적으로 형성됨에 따라 간단한 전구체로부터 복잡한 분자의 합성을 가능하게 한다. 따라서 연속 반응은 주로 카이랄 구축 단위, 제약, 전합성 등의 분야에서 빠르게 성장하고 있다. 이 논문에서는 카이랄 옥사자보롤리디늄 이온 촉매를 기반으로 오쏘-퀴논 메타이드를 이용한 입체선택적인 연속 반응들과 프리델-크래프츠 촉매반응이 연구되었다. 처음 소개되는 연속 반응은 α-다이아조에스터와 오쏘-퀴논 메타이드를 이용한 삼각고리화 반응/분자내 재배열 연속 반응을 통한 입체선택적인 2-아릴-2,3-다이하이드로 벤조퓨란의 합성이다. 카이랄 2-아릴-2,3-다이하이드로 벤조퓨란 유도체들은 수 많은 생리활성 물질들의 대표적인 카이랄 구축 단위로 알려져 있다. 카이랄 옥사자보롤리디늄 이온 촉매를 기반으로 하여, 사차 탄소를 포함한 연속적인 카이랄 센터를 가지고 있는 다양한 구조의 2-아릴-2,3-다이하이드로 벤조퓨란 유도체들이 높은 수율과 입체 선택성으로 합성되었다. 두 번째 연속 반응은 카이랄 옥사자보롤리디늄 이온 촉매, α-알킬-α-다이아조에스터와 오쏘-퀴논 메타이드를 이용한 입체선택적인 삼각고리화 반응/호모다이에닐 [1,5]-수소 이동 촉매 반응의 개발이다. 이 반응을 통해 합성된 라우훗-쿠리어 화합물은 다양한 작용기를 가지고 있으며 높은 수율과 입체 선택성으로 합성되었다. 합성된 화합물들은 다양한 쿠마린 유도체와 다른 종류의 라우훗-쿠리어 화합물로 변환시킴으로써 본 반응의 유용함을 보여주었다. 마지막으로, 퓨란과 오쏘-퀴논 메타이드를 이용한 매우 입체선택적인 프리델-크래프츠 반응의 개발이다. 카이랄 삼아릴탄소 화합물 유도체는 염료, 지시약, 생물학적 시료 등 다양한 분야에 적용된다. 카이랄 옥사자보롤리디늄 이온촉매와 퓨란 화합물을 통해 전에 개발되지 않은 새로운 구조의 입체선택적인 삼아릴탄소 화합물을 높은 수율과 입체 선택성으로 합성할 수 있었다.

Tandem C-C Bond Formations and Retro-ene Reactions Using Stable Precursors of Allylic Sulfinic Acid

최진 서울대학교 대학원 2016 국내박사

The allylic sulfinic acid rearrangement is a pericyclic process involving reductive alkene transposition via extrusion of sulfur dioxide (SO2) and 1,5- hydrogen shift. This retro-ene reaction of potential utility, however, has not been studied well due to the difficulties associated with preparing sulfinic acids and their instability. Therefore, preparing sulfinic acids from stable precursors under mild reaction conditions is important for the development of synthetically useful methods that combines the power of organosulfur chemistry and sulfinyl retro-ene reactions. This thesis describes research directed at the development of tandem C-C bond formation and retro-ene reactions using stable precursors of allylic sulfinic acids. Starting with testing various sulfones for their potential as sulfinic acid precursors (Chapter 1), studies have focused on tandem Diels-Alder and retro-ene reactions making use of (tert-butyl)dimethylsilyloxymethyl (TBSOM) substituted sulfones as precursors of sulfinic acids (Chapter 2). In addition to the cycloaddition, the alkylation of sulfones has also been explored (Chpater 3). The tandem sequence of alkylation with 5-methyl-1,3,4-thiadiazole (TD) substituted sulfones and removal of SO2 via a sulfinyl retro-ene reaction constitutes an efficient method for the stereoselective synthesis of functionalized alkenes. DFT computation studies have been carried out for the experimental results using GAMESS package, and the reaction profiles of various substrates have been analyzed. (Chapter 4). 알릴 설핀산 자리옮김 반응은 1,5 수소옮김과 이산화황을 배출을 통해서 환원 전이된 알켄 형성이 관여되는 고리형 협동 과정이다. 이러한 레트로-엔 반응은 잠재적인 유용성이 있지만 알릴 설핀산의 합성과 안정성을 확보하기 힘든 문제 때문에 유기합성분야에서 연구가 많이 되지 않았다. 따라서 설핀산의 안정한 전구체로부터 온화한 반응 조건에서 설핀산을 만들어 내는 일은 유기황화학과 설피닐 레트로-엔 반응과의 결합을 통해 합성적으로 유용한 방법론 개발에 있어서 중요하다. 이 논문은 알릴 설핀산의 안정한 전구체를 이용해서 탄소-탄소 결합 형성반응과 레트로-엔 반응을 결합한 새로운 연쇄반응에 대한 연구를 설명하고자 한다. 잠재적인 설핀산 전구체로서 다양한 설폰화합물을 시작으로 (1장) (tert-butyl)dimethyl- silyloxymethyl (TBSOM) 설폰을 설핀산의 전구체로 활용하여서 디엘스-알더 반응과 레트로-엔 연쇄반응을 중심으로 연구하였다. (2장) 고리첨가 반응 이외에도, 설폰의 알킬화 반응 역시 탐구하였다. 5-methyl-1,3,4-thiadiazole (TD)이 치환된 설폰의 알킬화 반응과 레트로-엔 반응을 통한 이산화황 제거하는 연쇄반응을 통해서 입체 선택적인 다양한 기능화 알켄의 효율적인 합성법을 개발하였다. (3장) 마지막으로 실험결과를 GAMESS 패키지를 이용해서 DFT 계산을 수행하고 다양한 기질에 대해서 실험결과를 해석하는 일을 진행하였다. (4장)

1. Synthesis of indole via tandem cyclization catalyzed by Pd–Fe3O4 nanocrystals2. Sulfonyl fluoride synthesis by multicomponent reaction with aryne and sulfuryl fluoride

권정민 서울대학교 대학원 2019 국내박사

With the increased concerns about economical and environment issues, more efficient and environmentally benign protocols for the synthesis of valuable organic compounds are being developed extensively. In this respect, two types of methodologies, tandem reactions and multicomponent reactions, have received much attention since they enable development of efficient synthetic routes by transforming multiple reactions into a single synthetic operation or by constructing diverse complex molecules through the combination of multiple starting materials. In this dissertation, developments of a new tandem reaction and a new multicomponent reaction are described, which afford important indole and sulfonyl fluoride derivatives, respectively. Chapter 1 describes the synthesis of indole derivatives via a palladium-catalyzed Sonogashira coupling reaction followed by tandem cyclization. This method allowed us to obtain 2-substituted indole derivatives with high atom efficiency, saving time and resources. In addition, the Pd–Fe3O4 nanoparticle catalyst could be recovered with an external magnet and reused up to ten times without the loss of its catalytic activity. Chapter 2 describes the synthesis of arenesulfonyl fluoride derivatives from sulfuryl fluoride, arynes, and amines via a multicomponent reaction. This novel and practical protocol allow for the direct synthesis of sulfonyl fluoride derivatives under mild transition-metal-free conditions. The simple and powerful approach also enabled participation of other nucleophiles such as isocyanides, imines, and phosphines in the multicomponent coupling process for the preparation of diverse sulfonyl fluoride derivatives. 경제성과 환경에 관한 이슈는 점점 중요해지고 있고, 따라서 복잡하고 가치 있는 분자를 생산하기 위한 효율적이고 친환경적인 합성 방법은 유기화학 분야에서 꾸준히 개발되고 있다. 이러한 점에서 여러 반응을 한 번의 실험을 통해 보내는 연쇄반응과 여러가지 출발 물질의 조합을 통해 다양하고 복잡한 화합물을 얻을 수 있는 다분자 반응은 효율적인 합성 방법을 가능하게 한다는 점에서 많은 관심을 받고 있다. 본 학위 논문은 연쇄반응을 통한 인돌 합성 방법 개발과 다분자 반응을 이용한 설포닐 플로라이드 합성 방법 개발에 관한 연구를 다룬다. 제 1 장에서는 소노가시라 반응과 고리화반응의 연쇄반응을 통해서 유용한 화합물인 인돌 합성법의 개발을 다룬다. 개발된 반응은 원자 경제적이고, 친환경적인 방법으로 2번 위치에 치환기가 있는 인돌 화합물을 합성할 수 있다. 또한 팔라듐-산화철 나노촉매는 외부자석을 통해 손쉽게 회수할 수 있으며, 10번의 재사용 실험에서도 촉매 활성이 유지 되었다. 제 2 장에서는 설퍼릴 플로라이드, 벤자인, 그리고 아민의 다분자 반응을 통한 설포닐 플로라이드 합성법의 개발을 다룬다. 개발된 반응은 새롭고 실용적인 합성법으로 전이금속 촉매 없이, 온화한 반응 조건에서 설포닐 플로라이드 작용기를 한번에 도입할 수 있다. 또한 아이소사이아나이드, 이민, 포스핀과 같은 다른 친핵체 사용을 통해, 다양한 설포닐 화합물 화합물을 합성할 수 있다.

Silver-Mediated tandem reaction을 통한 2-브로모메틸렌-테트라하이드로퓨란의 합성방법 연구

이현지 서울대학교 대학원 2012 국내석사

Exocyclic β-bromo enol ether는 vinyl halide 작용기와 enol ether 작용기를 모두 가지고 있어 hetero-Diels-Alder 반응이나 electrophilic addition과 같은 chemical transformation 연구에 유용한 모핵이다. 알려진 반응으로 이러한 모핵을 얻기 위해서는 적절한 기질을 출발물질로 하여 단계적인 반응을 통해 합성할 수 있었다. 본 연구에서는 보다 효율적이며 경제적인 tandem reaction을 통해 exocyclic β-bromo enol ether를 합성하고자 하였다. Cyclic enol ether는 전이금속을 이용한 intramolecular heterocyclization 을 통해 합성할 수 있고, 특히 gold나 silver는 exo-dig 생성물을 선택적으로 합성하는 효과적인 전이금속이라 알려져 있다. 또한 silver는 silyl-protected acetylene을 출발물질로 하여 desilylative bromination을 in situ로 진행할 수 있다고 연구된 바 있다. 이러한 선행연구를 바탕으로, acetylenic alcohol을 출발물질로 하여 silver-mediated tandem reaction을 통해 exocyclic β-bromo enol ether 모핵을 도입하는 합성방법을 고안하였다. 이러한 합성방법에 AgF/NBS system이 가장 적절한 것을 발견하였고, 유용성을 입증하기 위하여 pachastrissamine의 전합성을 진행하였다. The exocyclic β-bromo enol ether is a synthetically useful functional moiety in the preparation of functionalized oxygen heterocycles because it contains both a vinyl halide moiety and an enol ether functionality on the periphery of the oxygen heterocycle. This synthetically valuable moiety has previously been accessible primarily through a stepwise conversion of the appropriate substrate. The intramolecular heterocyclization to be a convenient way to access the cyclic enol ether moiety. This cyclizations can be driven by transition metal catalysts, and the regioselectivity of these reactions varies depending on the metal and the conditions employed. Among the metals thus far reported for these reactions, silver and gold have been demonstrated to be the most effective and selective for the formation of exo-dig products. We envisioned that this functional moiety could be obtained directly from the silylacetylenic alcohols via tandem silver(I)-mediated desilylative bromination and heterocyclization. We found that the AgF/NBS system was effective for this purpose. To demonstrate the synthetic potential of the developed method, a brief total synthesis of pachastrissamine was successfully attempted.

Synthesis and characterization of highly durable nanocatalysts by protecting active sites

전우주 Seoul National University 2016 국내박사

At present, the practical application of nanocatalysts is hindered by their low durability. To overcome this limitation, in this thesis, I synthesized highly durable nanocatalysts by protecting the catalyst active sites and then characterized the products. By immobilizing the acid and base catalysts on the nanomaterial surface, I secured the activity of each acid or base catalyst. In the case of the oxygen reduction reaction (ORR) catalyst, the nanoparticles (NPs) are protected from dissolution and agglomeration under the harsh fuel cell operating conditions by coating the nanocatalyst surface with a thin N-doped carbon shell. Following the introduction chapter, Chapter 2 describes the successful synthesis of a magnetically separable mesoporous site-isolated acid-base catalyst using a one-pot reaction. The catalyst showed excellent performance with very high yield and selectivity for the conversion of benzaldehyde dimethyl acetal to 1-nitro-2-phenylethylene via benzaldehyde using tandem acid-catalyzed deacetalization and base-catalyzed Henry reaction. The catalyst could be easily recovered using a magnet and dispersed in subsequent reaction mixtures, enabling recycling of the catalyst for up to five uses without loss of catalytic activity. Furthermore, comparative studies reveal that the larger-pore materials exhibited higher catalytic activity than the smaller-pore materials. In Chapter 3, I present the synthesis of highly durable and active intermetallic ordered face-centered tetragonal (fct)-PtFe NPs coated with a “dual-purpose” N-doped carbon shell. Ordered fct-PtFe NPs with a size of only a few nanometers were obtained by the thermal annealing of polydopamine-coated PtFe NPs, and the N-doped carbon shell formed in situ from the dopamine coating could effectively prevent the coalescence of NPs. This carbon shell also protects the NPs from detachment and agglomeration as well as dissolution under the harsh fuel cell operating conditions. By controlling the thickness of the shell below 1 nm, I achieved excellent protection of the NPs as well as high catalytic activity, as the thin carbon shell is highly permeable for the reactant molecules. The mass activity and specific activity of the ordered fct-PtFe/C nanocatalyst coated with an N-doped carbon shell are 11.4 and 10.5 times higher, respectively, than those of a commercial Pt/C catalyst. Moreover, a membrane electrode assembly (MEA) fabricated using this catalyst exhibited long-term stability for 100 h without significant activity loss. In situ X-ray absorption near edge structure (XANES) and energy-dispersive X-ray spectroscopy (EDS) studies confirmed that the ordered fct-PtFe structure is critical for the long-term stability of this nanocatalyst. The strategy developed herein, namely, utilizing an N-doped carbon shell to obtain small ordered-fct PtFe nanocatalysts and protect the catalyst during fuel cell cycling, is expected to provide a simple and effective route for the commercialization of fuel cells.

로듐(I)촉매 하에서 하이드로아실화 반응과 연속적인 반응을 통한 케톤의 합성

차경미 연세대학교 대학원 2009 국내석사

본 연구에서는 알데하이드와 알켄, 그리고 알카인을 이용하여 새로운 케톤 화합물을 합성하는 데 목적이 있으며 로듐촉매 하에서 hydroacylation과 연속적인 반응들을 통하여 고부가가치를 지니는 케톤을 합성하고자 하였다. 이 때 (Ph3P)3RhCl (윌킨슨 촉매)와 2-아미노-3-피콜린을 함께 사용하는 chelation-assisted hydroacylation catalyst와 1차 아민 (n-hexylamine)과 유기산 (p-trifluoromethylbenzoic acid)을 함께 사용하는 복합촉매계를 사용하여 반응의 효율을 향상시킬 수 있었다. 알데하이드와 알카인, 그리고 알켄과의 반응선택성을 비교한 결과 알카인의 반응성이 알켄의 반응성보다 10배 이상 뛰어나다는 것을 확인하였으며 이러한 반응성의 차이가 본 실험에서 두 가지 케톤을 one-pot에 합성하는 전제조건이 된다. retro-Mannich type fragmentation과 hydroacylation이 적용되는 연속반응 (tandem reaction)을 통해 케톤화합물을 합성할 수 있으며 나아가서 알켄기와 알데하이드기가 한 분자 내에 존재하는 vinylbenzaldehyde에도 적용하여 별도의 알카인을 첨가함으로써 다이케톤 화합물을 생성하였다. 카이랄성을 가진 미르테날 (myrtenal)의 경우 서로 다른 알켄기들의 도입순서를 달리함으로써 enantiomer를 형성할 수 있었으며 말단 알카인의 수화반응 (hydration)과 연이은 하이드로아실화 반응을 통해 케톤화합물을 합성할 수 있었다. Hydroacylation과 연속된 retro-Mannich type fragmentation, hydration 반응들의 tandem reaction을 통하여 보다 다양한 케톤 화합물을 합성할 수 있었다.

RCM(ring-closing metathesis) 반응을 이용한 N-O 결합을 포함한 헤테로 고리 합성과 고체상 합성에서의 응용

이수지 연세대학교 대학원 2005 국내석사

Ruthenium 촉매를 이용한 상호교환 고리화 반응을 이용해서 Enyne 구조의 출발물질을 N-O bond를 포함한 헤테로 고리 형태로 합성했다. 이후 singlet oxygen을 이용한 Diels-Alder 반응을 통해 peroxide로 만들었다. 이를 환원시켜 diol 형태로 만든 후 oxidation 반응으로 lactone과 furan을 합성했다. Tandem 상호교환 고리화 반응을 이용해서 dienyne 구조를 갖는 화합물을 1,3-conjugated diene 형태의 화합물로 합성했다.위 결과를 고체상 합성에 응용하기 위해 용액상에서 모델 반응을 연구하였다.The enyne-RCM(ring closing metathesis) adducts were transformed into the cyclic peroxides containing an N-O bond by singlet oxygen mediated Diels-Alder reaction. Then the peroxides were converted into furans and α,β-unsaturated γ-butyrolactones by reductive cleavage of the peroxide bond followed by oxidation of the alcohols. And the 1,3-conjugated diene containing an N-O bond were synthesized through tandem RCM reactions. Model studies for solid-phase synthesis were carried out in solution phase.

Synthesis of pyrazolone sulfonyl chlorides and the development of DABCO-based catalysts and reagents

정길수 Graduate School, Yonsei University 2021 국내박사

핵심적인 중간체 설포닐클로라이드계열 화합물의 합성법을 설계 했고 추가적인 반응최적화를 통해서 설폰아미드 포함한 화합물들을 합성 했다. 본 신규한 유도체의 mTORC1 저해 효과는 우수하다. DABCO를 이용한 치아졸리딘-2,4-디온 및 전자부족 이중결합 화합물을 이용한 신규 유기화학반응을 개발했다. 또한 치아졸리딘-2,4-디온의 양쪽에 동시 치환기를 붙이기위해 DABCO를 이용한 유기화학반응을 개발했다. 마지막으로 신규 DABCO를 포함한 멜드럼산 시약을 합성했고 본 시약의 화학적인 용도를 검토 했다. Described is a concise synthetic route to key sulfonyl chloride intermediates that were further transformed into a series of sulfonamide compounds and were screened as potential mTORC1 inhibitors that target the leucyl-tRNA synthetaseRagD interaction. Development of novel organic reaction methodologies consisting of a DABCO catalyzed aza-Michael reaction of thiazolidine-2,4-dione towards electron deficient alkenes and a DABCO-Succinic acid catalyzed tandem aza-Michael/Knoevenagel reaction for the difunctionalization of thiazolidine-2,4- dione was achieved. Finally, a novel DABCO-derived Meldrum’s acid was developed and its synthetic applications related to the functionalization of indoles were briefly explored.

Electrocatalytic CO2 reduction reaction on copper : designs toward product selectivity optimization

김주연 Graduate School, Yonsei University 2023 국내박사

Encountering an environmental crisis from an atmospheric CO2 surge, the research demand on the electrochemical carbon dioxide reduction reaction (CO2RR) has increased. Foremost, research on carbon dioxide reduction reaction (CO2RR) at Cu has been considered especially promising for its capability of CO2 conversion into valuable chemical fuels without emitting pollutants. However, two hurdles are still unsolved in the selective production of desired chemical fuels, even for a promising copper-based carbon dioxide reduction reaction (CO2RR). One is a competitive hydrogen evolution reaction (HER) that proceeds at a potential range-reducing carbon dioxide, and another is a unveiled reaction mechanism stemming from byproducts accompanying complex reaction steps. To overcome these hurdles and improve the selectivity of desired products, I’ve developed three research projects to control electrode surface-adsorbed carbon monoxide (COads) and electrode surface-adsorbed hydrogen (Hads). Firstly, I found that electrodeposited-Cu10Ag14Hg0.6 multimetallic films displayed an improved selectivity of C2 chemicals production in carbon dioxide reduction reaction (CO2RR), with highly suppressed hydrogen evolution reaction (HER). To elucidate the improved reaction mechanism at electrodeposited-Cu10Ag14Hg0.6 multimetallic films, surface-interrogation scanning electrochemical microscope (SI-SECM) and in-situ IR spectroscopy was used. These surface analysis methods revealed that electrode surface-adsorbed hydrogen (Hads) was suppressed and electrode surface-adsorbed carbon monoxide (COads) was increased at the developed catalyst. These results supported that Ag and Hg metal incorporation led to C2 selectivity enhancement by surface dynamics changes. Secondly, I designed a Cu-Ag Bipotentiostatic reaction system and measured CO efficiency in CO2-CO-C2 production made between two working electrodes (Cu and Ag). Through the unique capability of this system, I applied CO efficiency calculation that had been limited in the precedent literature. By applying the potential insufficient to produce C2 from CO2 reduction on Cu, I tried to minimize interference of C2 from Cu sole operation (CO2 to C2). Through the optimization process of various reaction factors (distance between Cu and Ag, applied potential at Ag (EAg), applied potential at Cu (ECu), and cation composition in the electrolyte), the selectivity of C2+ could be vastly improved (67% including 6.5% 1-PrOH). For last, I developed the reactor to modulate electrode surface temperature and investigated the reactivity of carbon dioxide reduction reaction (CO2RR). The COMSOL-based simulation revealed that electrode surface temperature could be depressed up to -4.0℃ when the thermoelectric module was set at -40℃ temperature. Combined with the potential-pulse program, surface chilling at subzero (-40℃ thermoelectric module temperature and -4.0℃ copper foil) improved the reactivity of CH4 at large amounts (80%). Compared to the bath cooling reactor (5℃), the selectivity of CH4 in surface chilling was 9% higher even without additional overpotential consumption (cathodic potential at surface chilling and bath cooling was -1.2 V and -1.5 V vs. RHE). By in-situ spectroscopic analysis and COMSOL-based simulation result, this reactivity improvement is presumably due to increased residence time of electrode surface-adsorbed carbon monoxide (COads) and increased CO2 concentration at electrode peripheral. Toward the dream of the carbon-neutral strategy to complete, many problems were still left unsolved in the carbon dioxide reduction reaction (CO2RR). However, I believe these pieces of novel research keep going will bring the dream come to reality finally.

Enantioselective synthesis of (S)-4-methyleneglutamic acid via tandem Michael reaction-elimination under phase-transfer catalytic conditions

강석훈 서울대학교 대학원 2010 국내석사