Asymmetric total syntheses of (+)-2,5-dideoxy-2,5-imino-<small>D</small>-glucitol [(+)-DGDP] and (−)-1-deoxymannojirimycin [(−)-DMJ] <i>via</i> an extended chiral 1,3-oxazine

Myeong, In-Soo,Jung, Changyoung,Kim, Ji-Yeon,Park, Seok-Hwi,Ham, Won-Hun Elsevier 2018 Tetrahedron letters: the international organ for t Vol.59 No.25

<P><B>Abstract</B></P> <P>The asymmetric total syntheses of (+)-2,5-dideoxy-2,5-imino-<SMALL>D</SMALL>-glucitol [(+)-DGDP] <B>1</B> and (−)-1-deoxymannojirimycin [(−)-DMJ] <B>2</B> were achieved using an extended chiral 1,3-oxazine. The key synthetic strategies included extension of the chirality of <I>anti</I>,<I>syn</I>-oxazine <B>3</B> using diastereoselective dihydroxylation, and piperidine and pyrrolidine ring formation. Starting from readily available <I>anti</I>,<I>syn</I>-oxazine <B>3</B>, (+)-DGDP <B>1</B> was synthesized in 5 steps with 31.6% overall yield and (−)-DMJ <B>2</B> was synthesized in 4 steps with 60.6% overall yield.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Reporting a total synthesis of (+)-DGDP, a polyhydroxylated pyrrolidine. </LI> <LI> Reporting a total synthesis of (−)-DMJ, a polyhydroxylated piperidine. </LI> <LI> Highly stereoselective dihydroxylation was accomplished by Osmium tetroxide. </LI> <LI> A novel chiral synthon <I>anti</I>,<I>syn</I>,<I>anti</I>-oxazine was used for the total syntheses. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

“K-synthesis”: Recent advancements in natural product synthesis enabled by unique methods and strategies development in Korea

한순규 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.3

Natural product synthesis has lain at the heart of organic chemistry. Complex structures of natural products have inspired chemists to develop new methods and strategies. The utility and robustness of newly developed methodologies have been tested by their application into total synthesis. With the necessity to establish a solid health-related and biomedical Korean industrial ecosystem, a historically belittled sector when compared to well-invested manufacturing and electronics industries in Korea, there has been enormous recent progress in the Korean organic chemical research. Accordingly, impressive syntheses of complex secondary metabolites that feature unique tactics and ingenious strat- egies have been reported by synthetic organic chemists in Korea. Herein, recent advancements (mostly after 2010) in natural product synthesis from Korea are depicted. Representative accomplishments from researchers in Korea are presented with an emphasis on unique methods and strategies that are uti- lized into their synthetic approaches.

Total Synthesis and Configurational Validation of (+)‐Violapyrone C

Lee, Jong Seok,Shin, Junho,Shin, Hee Jae,Lee, Hwa‐,Sun,Lee, Yeon‐,Ju,Lee, Hyi‐,Seung,Won, Hoshik WILEY‐VCH Verlag 2014 EUROPEAN JOURNAL OF ORGANIC CHEMISTRY Vol.2014 No.21

<P><B>Abstract</B></P><P>Gold(I)‐catalyzed intramolecular 6‐<I>endo</I>‐<I>dig</I> cyclization of <I>tert</I>‐butyl ynoates afforded α‐pyrone cores of violapyrones. Moreover, this reaction was successfully applied to the stereospecific syntheses of (+)‐ and (–)‐violapyrone C, which allowed the absolute configuration of natural (+)‐violapyrone C to be assigned by comparison of the optical rotations. This first total synthesis, which proceeded in 22 % yield over 10 steps from (<I>S</I>)‐(–)‐2‐methylbutanol, features silver(I) oxide promoted monobenzylation of 1,4‐butanediol, Wittig olefination, Claisen condensation, Corey–Fuchs reaction, and gold(I)‐catalyzed α‐pyrone synthesis.</P>

A Total Synthesis of Aliskiren Starting from D-Tartrate Diester

Kim, Ji Hei,Ko, Soo Y. Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.12

A formal total synthesis of aliskiren was accomplished. A key in our synthesis was to use the symmetric ciscisoid-cis-bis-lactone 3' as a precursor, which was prepared from D-tartrate diester. Appending the end groups and functional group transformations completed the synthesis.

A Total Synthesis of Aliskiren Starting from D-Tartrate Diester

Ji Hei Kim,고수영 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.12

A formal total synthesis of aliskiren was accomplished. A key in our synthesis was to use the symmetric ciscisoid- cis-bis-lactone 3' as a precursor, which was prepared from D-tartrate diester. Appending the end groups and functional group transformations completed the synthesis.

Solid‐Phase Total Synthesis of the Proposed Structure of Coibamide A and Its Derivative: Highly Methylated Cyclic Depsipeptides

Sable, Ganesh A.,Park, Jaekwan,Kim, Hyunsik,Lim, Soo‐,Jeong,Jang, Soonmin,Lim, Dongyeol WILEY‐VCH Verlag 2015 European Journal of Organic Chemistry Vol.2015 No.32

<P>The solid-phase total synthesis of the proposed structure of cyclic depsipeptide coibamide A and its derivative O-desmethyl coibamide A is reported. In this study, we demonstrate the solid-phase synthetic strategy and final solution-phase O-methylation for highly N-methylated cyclic depsipeptides. On-resin macrocyclization, N,N-dimethylation and solution-phase O-methylation were the key steps of these syntheses. The mass of synthetic coibamide A is consistent with that of the natural product according to liquid chromatography-mass spectroscopy (LCMS) analysis but significant differences are observed upon H-1 and C-13 NMR analysis. The 2D NMR analysis and modeling studies of the synthetic compound compared with the isolated natural compound revealed that either they are conformationally different or the stereochemistry of the natural product was incorrectly assigned.</P>

Formal Total Synthesis of (−)-Apicularen A by a Strategy Based on Ring-Closing Metathesis and Transannular Cyclization

Jung, Young-Hee,Kim, Young-Ju,Lee, Jieun,Tae, Jinsung WILEY-VCH Verlag 2007 Chemistry, an Asian journal Vol.2 No.5

<P>A formal synthesis of (−)-apicularen A, a potent antitumor agent with unique biological properties, has been completed in a 15-step sequence starting from a known, enantiomerically pure hydroxyepoxide, which was generated by using the Jacobsen hydrolytic-kinetic-resolution methodology. The 12-membered macrocyclic lactone in the target was constructed by ring-closing metathesis, and the trans-tetrahydropyran ring system was created through the transannular etherification of a hydroxyalkene.</P> <B>Graphic Abstract</B> <P>An antitumor ring: The unique biological properties and intriguing structure of (−)-apicularen A make it an attractive target for total synthesis. The key steps involve ring-closing metathesis (RCM) to form the macrocyclic lactone and transannular etherification of the resulting hydroxyalkene to form the trans-tetrahydropyran ring. Bn=benzyl, PMB=p-methoxybenzyl. <img src='wiley_img/18614728-2007-2-5-ASIA200700024-content.gif' alt='wiley_img/18614728-2007-2-5-ASIA200700024-content'> </P>

Aziridinyl imines in organic synthesis: Development of tandem reaction strategies and application to total synthesis of natural products

Lee, Hee-Yoon,Song, Seog-Beom,Kang, Taek,Kim, Yoon Jung,Geum, Su Jeong De Gruyter 2013 Pure and applied chemistry. Vol.85 No.4

<P>Aziridinyl imines are well-known carbene equivalents because they are precursors of diazo compounds from which reactive intermediates can be produced. These carbene equivalents can be utilized as zwitterionic species, diradicals, or 4π system for cycloaddition reactions. Thus, the intermediates derived from aziridinyl imines have been used in the sulfur-ylide-mediated epoxide formation, tandem free-radical reactions, or cyclopropanation reaction via carbene intermediates to form trimethylenemethane (TMM) diyls, which undergo [2 + 3] cycloaddition reactions to form cyclopentanoids. Diazo compounds generated from aziridinyl imines also react with allenes to form TMM diyls. This reaction was utilized in tandem cycloaddition reactions of linear substrates to form polyquinanes. These tandem reaction strategies were successfully applied to the total synthesis of various cyclopentanoid natural products.</P>

김기림 『시론』의 개작과정 연구

장철환(Jang Cheul-whoan) 한국근대문학회 2010 한국근대문학연구 Vol.11 No.2

본고는 서지적 차원에서, 1947년 11월 백양당에서 간행된 ??시론??의 개작 과정을 검토함을 일차적 목적으로 한다. ??시론??은 1930년대 ??조선일보??를 중심으로 발표된 34편의 소논문으로 구성된 책으로, 다양한 맥락과 시차를 갖는 독립된 글들의 집합이라고 할 수 있다. 즉 ??시론??은 내용상?구조상 여러 균열을 노정하고 있으며, 이러한 균열에 대한 봉합으로서 개작 양상은 그의 사유의 다층적 변화지점들을 보여준다고 할 수 있다. 따라서 ??시론??의 개작 과정의 구체적 양상들을 추적함으로써, 우리는 그의 시론의 사상적 궤적과 변이 양상을 추적할 수 있을 것이다. ??시론??의 개작에서 결정적 계기로 작용한 것은 1935년 12월에 있었던 임화와의 기교주의 논쟁이었다. 비록 미완으로 종결되긴 하지만, 논쟁의 결과 개작의 방향은 대체적으로 ‘시대성’ 혹은 ‘시대정신’을 강화하는 쪽으로 진행된다. 이는 ‘전체시론’의 형성 및 확대 과정에 잘 나타나 있는데, ‘내용과 형식의 통일’에서 ‘시(문학)와 현실의 종합’이라는 의미로의 확장이 그것이다. 결국 ??시론??의 개작 과정은 ‘경향파와 모더니즘의 종합’이라는 시대적 요청을 반영한, 일종의 외과적 봉합술이라고 할 수 있다. This article's primary aim is to analyze the adaptation process of Kim Ki-rim's ??Poetics?? on a bibliography basis. This book is made up 34 essays printed in 'Chosun-Ilbo', which is a collection with various contexts and point of views. So many cracks appear on ??Poetics?? in content and structure. The adaptation as a suture of these cracks shows up the various aspects of his thoughts. Therefore, to study on the adaptation process of Kim Ki-rim's ??Poetics?? is equal to study on the change of his thoughts. The decisive motive in the adaptation was the argument with 'Im-wha' named 'technicalism-dispute'. Though this dispute ended incomplete, his adaptation turned to a different direction, namely the direction to reinforce 'the spirit of the times'. This is reflected in the formation and development of 'the poetics of totality', that is the development from 'the synthesis of content and form' to 'the synthesis of poem and reality'. Finally the adaptation of ??Poetics?? is a surgical suture to meet the demands of the times, ‘the synthesis of Tendencygroup and modernism'.

Diastereomeric Resolution of a Racemic Biarylboronic Acid and Its Application to Divergent Asymmetric Total Syntheses of Some Axially Chiral Natural Products

Lee, Chun‐,Young,Cheon, Cheol‐,Hong WILEY-VCH 2016 Advanced Synthesis & Catalysis Vol.358 No.4

<P><B>Abstract</B></P><P>The asymmetric total syntheses of deshydroxytetramethylcupressuflavone and desmethylkotanin and the synthesis of a key intermediate in the previous synthesis of hibarimicinone are described using an axially chiral biarylboronic acid, prepared by the diastereomeric resolution of the corresponding <I>rac</I>‐boronic acid, as a common intermediate. Conversion of the boronic acid moiety into either a hydrogen atom or a hydroxy group by protodeboronation or oxidation enabled us to complete the total syntheses of deshydroxytetramethylcupressuflavone and desmethylkotanin and synthesis of a key intermediate in the previous total synthesis of hibarimicinone, respectively.</P>