WordNet

sound loudly and sonorously; "the bells rang" (同)peal
a toroidal shape; "a ring of ships in the harbor"; "a halo of smoke" (同)halo, annulus, doughnut, anchor ring
jewelry consisting of a circlet of precious metal (often set with jewels) worn on the finger; "she had rings on every finger"; "he noted that she wore a wedding band" (同)band
a characteristic sound; "it has the ring of sincerity"
a platform usually marked off by ropes in which contestants box or wrestle
the sound of a bell ringing; "the distinctive ring of the church bell"; "the ringing of the telephone"; "the tintinnabulation that so voluminously swells from the ringing and the dinging of the bells"--E. A. Poe (同)ringing, tintinnabulation
attach a ring to the foot of, in order to identify; "ring birds"; "band the geese to observe their migratory patterns" (同)band
make (bells) ring, often for the purposes of musical edification; "Ring the bells"; "My uncle rings every Sunday at the local church" (同)knell
final or ending; "the closing stages of the election"; "the closing weeks of the year"; "the closing scene of the film"; "closing remarks"
approaching a particular destination; a coming closer; a narrowing of a gap; "the ships rapid rate of closing gave them little time to avoid a collision" (同)closure
wearing a wedding ring; lawfully married; "a ringed wife"- Tennyson
having colored rings around the body
gymnastic apparatus consisting of a pair of heavy metal circles (usually covered with leather) suspended by ropes; used for gymnastic exercises; "the rings require a strong upper body"
a linguistic process of transposition of sounds or syllables within a word or words within a sentence

PrepTutorEJDIC

『指輪』 / 『輪』,環;輪形,円形 / (円形の)サーカス演技場,公演場,競技場;(ボクシング・レスリングの)リング / 《複数形で》(体操の)つり輪 / (不法な目的で結託した)(…の)徒党,一味《+『of』+『名』》 / (原子の)環 / …を円形に取り囲む,円で囲む《+『about』(『around』,《英》『round』)+『名,』+『名』+『about』(『around』,《英》『round』)+『名』》 / 〈動物〉‘に'鼻輪(首輪,足輪)をはめる / (遊びで)…‘に'輪を投げる / 環状に動く,輪を描く
〈鐘・ベルなどが〉『鳴る』 / 《『ring』+『形』〈補〉》(…のように)聞こえる / (…を)ベルを鳴らして求める《+『for』+『名』》 / 〈音声・楽器などが〉鳴り響く;〈場所が〉(音などで)満ちる《+『with』+『名』》 / 耳鳴りがする / 〈鐘・ベルなど〉‘を'『鳴らす』 / 〈人〉‘を'(鐘などを)『鳴らして呼ぶ』;…‘を'鐘を鳴らして知らせる / 《英》…‘に'電話をかける《+『up』+『名』,+『名』+『up』》 / 《単数形で》(鐘・ベルなどの)『鳴る音,響き』《+『of』+『名』》 / 鐘(ベルなど)を鳴らすこと;ベル(など)が鳴ること / 《単数形で》(…の)固有の響き,調子,感じ《+『of』+『名』》 / 《話》電話をかけること
閉じる,終りの / 〈U〉閉じること,閉鎖 / 〈C〉〈U〉終了,締め切り;決算
輪にある;環状の / 指輪をはめた

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/10/19 20:49:27」(JST)

wiki en

Ring-closing metathesis or RCM is a variation on olefin metathesis that allows the closing of previously hard to make rings (7-8 member rings in particular). RCM is simply an intramolecular olefin metathesis, yielding the cycloalkene and a volatile alkene, in this example ethene.

Many metathesis reactions with ruthenium catalysts are hampered by unwanted isomerization of the newly formed double bond and it is believed that ruthenium hydrides are responsible that form as a side reaction. In one study ^[1] it is found that isomerization is suppressed in the RCM reaction of diallyl ether with specific additives capable of removing these hydrides (scheme 2). Without an additive, the reaction product is 2,3-dihydrofuran and not the expected 2,5-dihydrofuran (together with the formation of ethylene gas). Radical scavengers such as TEMPO or phenol as an additive show the same picture but with additives such as 1,4-benzoquinone or acetic acid on the other hand isomerization is absent. Both additives are able to oxidize the ruthenium hydrides which may explain their behaviour.

Ring closing metathesis is important in total synthesis. One example is found in the synthesis of the naturally occurring cyclophane floresolide (Scheme 3, R=H).^[2]

References

^ Soon Hyeok Hong, Daniel P. Sanders, Choon Woo Lee, and Robert H. Grubbs (2005). "Prevention of Undesirable Isomerization during Olefin Metathesis" (Communication). J. Am. Chem. Soc. 127 (49): 17160–17161. doi:10.1021/ja052939w. PMID 16332044.
^ K. C. Nicolaou and Hao Xu (2006). "Total synthesis of floresolide B and 6,7-Z-floresolide B". Chemical Communications (6): 600–602. doi:10.1039/b517385j. PMID 16446822. In this reaction step the phenol protective group is a nitrobenzoate group which can be removed in the final step by potassium carbonate. The reaction product is a mixture of E and Z isomers. Although one prochiral center is present the product is racemic. Floresolide is an atropisomer as the new ring forms (due to steric constrains in the transition state) passing through the front of the carbonyl group in (blue) and not the back. The carbonyl group then locks the ring permanently in place.

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3. 指輪の除去手技 ring removal techniques
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English Journal

Stereoselective Total Synthesis of Carolacton.

Kuilya TK1, Goswami RK1.
Organic letters.Org Lett.2017 May 5;19(9):2366-2369. doi: 10.1021/acs.orglett.7b00903. Epub 2017 Apr 24.
PMID 28436677

Synthesis of Selectively Substituted or Deuterated Indenes via Sequential Pd and Ru Catalysis.

Jana A1, Misztal K2, Żak A2, Grela K2.
The Journal of organic chemistry.J Org Chem.2017 Apr 21;82(8):4226-4234. doi: 10.1021/acs.joc.7b00200. Epub 2017 Apr 12.
PMID 28332398

Locking Interconversion of Aromatic Oligoamide Foldamers by Intramolecular Side-chain Crosslinking: toward Absolute Control of Helicity in Synthetic Aromatic Foldamers.

Zheng L1, Yu C1, Zhan Y1, Deng X1, Wang Y1, Jiang H1.
Chemistry (Weinheim an der Bergstrasse, Germany).Chemistry.2017 Apr 19;23(22):5361-5367. doi: 10.1002/chem.201700134. Epub 2017 Mar 29.
PMID 28211205

Japanese Journal

Synthesis and biological activities of the tris-oxazole macrolactone analogs of mycalolides

Kita Masaki,Oka Hirotaka,Usui Akihiro,Ishitsuka Tomoya,Mogi Yuzo,Watanabe Hidekazu,北将樹,石塚智也,木越英夫
Tetrahedron 68(42), 8753-8760, 2012-10
… To develop an efficient synthetic route of mycalolides and to evaluate its functional mechanism of biological activities, tris-oxazole macrolactone analogs of mycalolides were synthesized through the use of ring-closing metathesis (RCM). …
NAID 120004898316