https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Multicomponent reactions (MCRs) are fundamentally different from two-component reactions in several aspects. Among the MCRs, those with isocyanides have developed into popular organic-chemical reactions in the pharmaceutical industry for the preparation of compound libraries of low-molecular druglike compounds. With a small set of starting materials, very large libraries can be built up within a short time, which can then be used for research on medicinal substances. Due to the intensive research of the last few years, many new backbone types have become accessible. MCRs are also increasingly being employed in the total synthesis of natural products. MCRs and especially MCRs with isocyanides offer many opportunities to attain new reactions and basic structures. However, this requires that the chemist learns the “language” of MCRs, something that this review wishes to stimulate.

Multicomponent Reactions with Isocyanides.

Once considered the 'holy grail' of organometallic chemistry, synthetically useful reactions employing C-H bond activation have increasingly been developed and applied to natural product and drug synthesis over the past decade. The ubiquity and relative low cost of hydrocarbons makes C-H bond functionalization an attractive alternative to classical C-C bond forming reactions such as cross-coupling, which require organohalides and organometallic reagents. In addition to providing an atom economical alternative to standard cross - coupling strategies, C-H bond functionalization also reduces the production of toxic by-products, thereby contributing to the growing field of reactions with decreased environmental impact. In the area of C-C bond forming reactions that proceed via a C-H activation mechanism, rhodium catalysts stand out for their functional group tolerance and wide range of synthetic utility. Over the course of the last decade, many Rh-catalyzed methods for heteroatom-directed C-H bond functionalization have been reported and will be the focus of this review. Material appearing in the literature prior to 2001 has been reviewed previously and will only be introduced as background when necessary. The synthesis of complex molecules from relatively simple precursors has long been a goal for many organic chemists. The ability to selectively functionalize a molecule with minimal pre-activation can streamline syntheses and expand the opportunities to explore the utility of complex molecules in areas ranging from the pharmaceutical industry to materials science. Indeed, the issue of selectivity is paramount in the development of all C-H bond functionalization methods. Several groups have developed elegant approaches towards achieving selectivity in molecules that possess many sterically and electronically similar C-H bonds. Many of these approaches are discussed in detail in the accompanying articles in this special issue of Chemical Reviews. One approach that has seen widespread success involves the use of a proximal heteroatom that serves as a directing group for the selective functionalization of a specific C-H bond. In a survey of examples of heteroatom-directed Rh catalysis, two mechanistically distinct reaction pathways are revealed. In one case, the heteroatom acts as a chelator to bind the Rh catalyst, facilitating reactivity at a proximal site. In this case, the formation of a five-membered metallacycle provides a favorable driving force in inducing reactivity at the desired location. In the other case, the heteroatom initially coordinates the Rh catalyst and then acts to stabilize the formation of a metal-carbon bond at a proximal site. A true test of the utility of a synthetic method is in its application to the synthesis of natural products or complex molecules. Several groups have demonstrated the applicability of C-H bond functionalization reactions towards complex molecule synthesis. Target-oriented synthesis provides a platform to test the effectiveness of a method in unique chemical and steric environments. In this respect, Rh-catalyzed methods for C-H bond functionalization stand out, with several syntheses being described in the literature that utilize C-H bond functionalization in a key step. These syntheses are highlighted following the discussion of the method they employ.

/pdf/rhodium-catalyzed-c-c-bond-formation-via-heteroatom-directed-1wd3dm1jdi.pdf

Rhodium-Catalyzed C-C Bond Formation via Heteroatom-Directed C-H Bond Activation

Green Chemistry is a relatively new emerging field that strives to work at the molecular level to achieve sustainability. The field has received widespread interest in the past decade due to its ability to harness chemical innovation to meet environmental and economic goals simultaneously. Green Chemistry has a framework of a cohesive set of Twelve Principles, which have been systematically surveyed in this critical review. This article covers the concepts of design and the scientific philosophy of Green Chemistry with a set of illustrative examples. Future trends in Green Chemistry are discussed with the challenge of using the Principles as a cohesive design system (93 references).

Green Chemistry: Principles and Practice

N-Heterocyclic Carbenes in Late Transition Metal Catalysis

本研究では，既往の研究で開発した被害情報収集システムと被害情報収集伝達システムの2つのシステムと従来からの紙による調査方法とを詳細に見直し，調査時の効率化を図るために既往の被害情報収集支援システムの改良を行った．調査時の効率化を図る方法として，アドホック通信を利用した調査員同士の連携機能，及び調査員の安全確保を目的とした火災延焼，交通状況のシミュレーション解析システムとの連携機能の2つの開発を行った．開発したシステムの有用性を確認するために，愛知県豊橋市において開発した機能の実証実験を実施し，その有用性を確認した．

A Study on Intelligence Sharing using the Support System for Disaster Information Collection with Information and Communication Technology

Extractive Nitrogenous Components of the Blue-Green Alga Spirulina maxima

PROBLEM TO BE SOLVED: To provide a method for synthesizing a benzometalol such as silol, easy in modification with substituent(s) and simple in the reaction itself as well. SOLUTION: The method for synthesizing the benzometalol(3) as shown in the Figure comprises conducting a [2+2+2] addition cyclization reaction between a diyne compound(1) and a monoyne compound(2). COPYRIGHT: (C)2008,JPO&INPIT

Method for synthesizing benzometalol and new diyne compound

Silole skeletons are constructed by ring-closing olefin metathesis of silicon-tethered dienes and trienes. A silicon-tethered enyne is also converted to a 2-alkenyl-1-silaindene via ruthenium-catalyzed ring-closing enyne metathesis.

Synthesis of Silole Skeletons via Metathesis Reactions

食 品分 野で使用 され る超臨界流体 はこれ まで のところ 超臨界二酸化 炭素 に限 られ て いる。 二酸化炭素 は,臨 界温 度が31.1°C と常温 に近 く,臨 界 圧 力 も73.8bar (75.2kg/cm2)と 比較的低い ので 超 臨界状態 にす るた め のエネルギーが少 な くてす み,さ らに無極性かつ不然性 と化学的 に も安定 で安全性 が高 い上,た とえ漏出 して も 環境汚 染の虞 がな く,し か も安価 で入手 しやすいな ど, 多 くの利点 を もっているためである。 超 臨界二酸化炭素抽 出の食品へ の適用では,商 業 ベー スで実施 され てい る コー ヒーの青豆 の脱 カフェイ ン1), ホ ップエキスの製造2)な どが よ く知 られ てお り,大 豆3)~ 5) ,ピ ーナ ツ4),綿実4),6),コ コヤシ7),バ ター8),ト ウモ ロコシはい芽9),10),小麦 はい芽11)などか らの油の抽 出 も 試 み られ ている。水産物 について は,筆 者 らが行ったナ ンキ ョクオキアミ12),13),微細藍藻 ス ピル リナ14),15)など か らの油 の抽 出実験以外 にはほとんど研 究例がなかった が,最 近 になって魚油 に豊富 に含まれ,そ の抗 動脈硬化 作用 が注 目されてい るイ コサペ ンタエ ン酸の抽 出 ・精製 に超臨界二酸化炭素抽 出法 を適用 した成果が相次 いで発 表 され始 めて いる16)。ここで は,筆 者 らの研究 を中心 に 水産物抽 出へ の応用例 をと りま とめてみたい。

https://www.jstage.jst.go.jp/article/jos1956/35/4/35_4_260/_pdf

Masahiro Murakami

Papers

A Study on Intelligence Sharing using the Support System for Disaster Information Collection with Information and Communication Technology

Extractive Nitrogenous Components of the Blue-Green Alga Spirulina maxima

Method for synthesizing benzometalol and new diyne compound

Synthesis of Silole Skeletons via Metathesis Reactions

Application of Supercritical Fluid Extraction to Aquatic Organisms