Thorpe–Ingold effect

The Thorpe–Ingold effect, gem-dimethyl effect, or angle compression is an effect observed in chemistry where increasing steric hindrance favours ring closure and intramolecular reactions. The effect was first reported by Beesley, Thorpe, and Ingold in 1915 as part of a study of cyclization reactions.[1] It has since been generalized to many areas of chemistry.[2]

The comparative rates of lactone formation (lactonization) of various 2-hydroxybenzenepropionic acids illustrate the effect. The placement of an increasing number of methyl groups accelerates the cyclization process.[3]

One application of this effect is addition of a quaternary carbon (e.g., a gem-dimethyl group) in an alkyl chain to increase the reaction rate and/or equilibrium constant of cyclization reactions. An example of this is an olefin metathesis reaction:[4] In the field of peptide foldamers, amino acid residues containing quaternary carbons such as 2-aminoisobutyric acid are used to promote formation of certain types of helices.[5]

One proposed explanation for this effect is that the increased size of the substituents increases the angle between them. As a result, the angle between the other two substituents decreases. By moving them closer together, reactions between them are accelerated. It is thus a kinetic effect.

The effect also has some thermodynamic contribution as the in silico strain energy decreases on going from cyclobutane to 1-methylcyclobutane and 1,1-dimethylcyclobutane by a value between 8 kcal/mole[6] and 1.5 kcal/mole.[7] A noteworthy example of the Thorpe-Ingold effect in supramolecular catalysis is given by diphenylmethane derivatives provided with guanidinium groups.[8] These compounds are active in the cleavage of the RNA model compound HPNP. Substitution of the methylene group of the parent diphenylmethane spacer with cyclohexylidene and adamantylidene moieties enhances catalytic efficiency, with gem dialkyl effect accelerations of 4.5 and 9.1, respectively.

See also

References

  1. ^ Beesley, Richard Moore; Ingold, Christopher Kelk; Thorpe, Jocelyn Field (1915). "CXIX.–The formation and stability of spiro-compounds. Part I. Spiro-Compounds from cyclohexane". J. Chem. Soc., Trans. 107: 1080–1106. doi:10.1039/CT9150701080.
  2. ^ Shaw, B. L. (1975). "Formation of Large Rings, Internal Metalation Reactions, and Internal Entropy Effects". Journal of the American Chemical Society. 97 (13): 3856–3857. doi:10.1021/ja00846a072.
  3. ^ Michael N. Levine, Ronald T. Raines "Trimethyl lock: a trigger for molecular release in chemistry, biology, and pharmacology (perspective)" Chem. Sci., 2012, volume 3, 2412–2420. doi:10.1039/C2SC20536J
  4. ^ Fürstner, A; Langemann, K. (1996). "A Concise Total Synthesis of Dactylol via Ring Closing Metathesis" (PDF). J. Org. Chem. 61 (25): 8746–8749. doi:10.1021/jo961600c. hdl:11858/00-001M-0000-0024-07AC-2. PMID 11667847.
  5. ^ Misra, Rajkumar; George, Gijo; Reja, Rahi M.; Dey, Sanjit; Raghothama, Srinivasarao; Gopi, Hosahudya N. (2020). "Structural insight into hybrid peptide ε-helices". Chemical Communications. 56 (14): 2171–2173. doi:10.1039/C9CC07413A. ISSN 1359-7345. PMID 31970340. S2CID 210872237.
  6. ^ Ringer, Ashley L.; Magers, David H. (1 March 2007). "Conventional Strain Energy in Dimethyl-Substituted Cyclobutane and the gem -Dimethyl Effect". The Journal of Organic Chemistry. 72 (7): 2533–2537. doi:10.1021/jo0624647. PMID 17341119.
  7. ^ Bachrach, Steven M. (1 March 2008). "The gem -Dimethyl Effect Revisited". The Journal of Organic Chemistry. 73 (6): 2466–2468. doi:10.1021/jo702665r. PMID 18278945.
  8. ^ Salvio, Riccardo; Mandolini, Luigi; Savelli, Claudia (19 July 2013). "Guanidine–Guanidinium Cooperation in Bifunctional Artificial Phosphodiesterases Based on Diphenylmethane Spacers; gem -Dialkyl Effect on Catalytic Efficiency". The Journal of Organic Chemistry. 78 (14): 7259–7263. doi:10.1021/jo401085z. PMID 23772969.

Read other articles:

Cophylinae

Cophylinae Anodonthyla boulengerii Klasifikasi ilmiah Kerajaan: Animalia Filum: Chordata Kelas: Lissamphibia Ordo: Anura Subordo: Neobatrachia Famili: Microhylidae Subfamili: CophylinaeCope, 1889 Genera 7 genus, (58+ species) lihat teks. Cophylinae adalah salah satu subfamili dari famili Microhylidae yang ditemukan di daerah Madagaskar. Subfamili ini memiliki setidaknya 58 spesies dalam 7 genus. Genus Anodonthyla Müller, 1892 (11 species) Cophyla Boettger, 1880 (3 species) Madecassophryne G...

 

Graham Hancock

Graham HancockLahir02 Agustus 1950 (umur 73)Edinburgh, Skotlandia, Britania RayaKebangsaanBritaniaWarga negaraBritaniaAlmamaterUniversitas DurhamPekerjaanPenulisDikenal atasPenulis, The Sign and the Seal, Fingerprints of the Gods, The Message of the Sphinx, Entangled Graham Hancock (lahir 2 Agustus 1950) adalah seorang penulis dan jurnalis Britania.[1] meliputi peradaban kuno, monumen batu atau megalitikum, mitos kuno dan data astronomi/astrologi dari masa lalu. Buku Hancock, Gr...

 

Fotboll vid internationella öspelen 2001 (herrar)

Fotboll vid internationella öspelen 2001 (herrar)EvenemangsfaktaDatum8–13 juli 2001Värdnation Isle of ManDeltagareAntal lag12StatistikMatcher24Mål89 (3,7 per match)0 Vinnare Guernsey (1:a titeln) Finalist Anglesey Trea Jersey  Föregående Följande  1999 Gotland Guernsey 2003   Kvalificerad för slutspel   Spel om femteplats   Spel om niondeplats Fotbollsturneringen vid internationella öspelen 2001 (herrar) avgjordes mellan den 8 och 13 j...

Maecenas E. Benton

American politician Maecenas Eason BentonFrom Volume 1 of 1899's Autobiographies and Portraits of the President, Cabinet, Supreme Court, and Fifty-fifth CongressMember of the U.S. House of Representativesfrom Missouri's 15th districtIn officeMarch 4, 1897 – March 3, 1905Preceded byCharles Germman BurtonSucceeded byCassius M. Shartel Personal detailsBornJanuary 29, 1848Dyersburg, TennesseeDiedApril 27, 1924(1924-04-27) (aged 76)Springfield, MissouriResting placeOdd ...

 

WUVN

TV station in Hartford, Connecticut WUVNHartford, ConnecticutUnited StatesChannelsDigital: 22 (UHF), shared with WUTH-CDVirtual: 18BrandingUnivision 18; Noticias Nueva InglaterraProgrammingAffiliations18.1: Univision18.4: LATVOwnershipOwnerEntravision Communications(Entravision Holdings, LLC)Sister stationsWUNI, WUTH-CDHistoryFirst air dateSeptember 25, 1954(69 years ago) (1954-09-25)Former call signsWGTH-TV (1954–1956)WHCT (1956–1972)WHCT-TV (1972–2001)Former channel number(s...

 

Bencana

Puing-puing dari gempa bumi San Francisco 1906, dikenang sebagai salah satu bencana alam terburuk dalam sejarah Amerika Serikat Bencana adalah rangkaian peristiwa yang mengancam dan mengganggu kehidupan masyarakat baik yang disebabkan oleh faktor alam atau non alam maupun faktor manusia sehingga mengakibatkan timbulnya korban jiwa, kerusakan lingkungan, kerugian harta benda dan dampak psikologis.[1] Bencana dalam bahasa inggris disebut dengan disaster, berasal dari kata Latin yaitu di...

Vindaloo

Untuk kegunaan lain, lihat Vindaloo (disambiguasi). VindalooVindalho babi yang disajikan di sebuah restoran Goa di Lisbon, PortugalJenisKariSajianHidangan utamaTempat asalIndiaDaerahGoaBahan utamaCabai, cuka, gula, jahe, rempah-rempahSunting kotak info • L • BBantuan penggunaan templat ini Buku resep: Vindaloo  Media: Vindaloo Vindaloo adalah sebuah masakan kari khas India yang berasal dari Goa, daerah sekitar Konkan serta berbagai daerah lain di India.[1] Hidan...

 

Saint George and the Dragon (Notke)

Sculpture by Bernt Notke Saint George and the Dragon by Bernt Notke Saint George and the Dragon (Swedish: Sankt Göran och draken) is a late medieval wooden sculpture depicting the legend of Saint George and the Dragon, located in Storkyrkan in Stockholm, Sweden. It is attributed to Bernt Notke and was commissioned by the Swedish regent Sten Sture the Elder. It was inaugurated in 1489. It has been described as an artistic high point in the artistic production of Bernt Notke. History The statu...

 

Armand Cure

Questa voce sugli argomenti giocatori di football americano statunitensi e cestisti statunitensi è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Armand Cure Nazionalità  Stati Uniti Altezza 183 cm Peso 90 kg Pallacanestro Ruolo Ala Termine carriera 1947 CarrieraGiovanili New Bedford High School1940-1943 R. Island RamsSquadre di club 1946-1947 Prov. Steamrollers12 Il simbolo → indica u...

Nazran

Nazran НазраньKotaPemandangan Nazran dari tepi Danau Nazran BenderaLambang kebesaranPeta lokasi Nazran NazranLokasi NazranTampilkan peta IngushetiaNazranNazran (Rusia)Tampilkan peta RusiaKoordinat: 43°13′N 44°46′E / 43.217°N 44.767°E / 43.217; 44.767Koordinat: 43°13′N 44°46′E / 43.217°N 44.767°E / 43.217; 44.767NegaraRusiaSubjek federalIngushetiaPendirian1781[1]Status sejak1967[1]Pemerintahan • ...

 

Army of One (film 2016)

Army of OnePoster rilis digitalSutradaraLarry CharlesProduser Emile Gladstone Jeremy Steckler James D. Stern Ditulis oleh Rajiv Joseph Scott Rothman Pemeran Nicolas Cage Wendi McLendon-Covey Rainn Wilson Russell Brand Denis O'Hare Paul Scheer Will Sasso Penata musikDavid NewmanSinematograferAnthony HardwickPenyuntingChristian KinnardPerusahaanproduksi Conde Nast Entertainment Endgame Entertainment Kasbah-Film Tanger Distributor TWC-Dimension Anchor Bay Entertainment Tanggal rilis 4 Nove...

 

Salvadoran Americans

Americans of Salvadoran birth or descent Ethnic group Salvadoran AmericansSalvadoreño-EstadounidensesTotal population2,480,509 (2022 American Community Survey)[1][2]0.75% of total U.S. population, 2021[2]Regions with significant populationsGreater Los Angeles, Houston, San Francisco Bay Area, Maryland, Washington, D.C., Dallas, New York City, Long Island, New Jersey, Greater Boston, Miami, Northern Virginia, Chicago, Atlanta, Charlotte, Las Vegas Valley, Fayetteville...

Buckwheat

Species of flowering plant in the family Polygonaceae This article is about a commonly cultivated crop plant. For other uses, see Buckwheat (disambiguation). Buckwheat Scientific classification Kingdom: Plantae Clade: Tracheophytes Clade: Angiosperms Clade: Eudicots Order: Caryophyllales Family: Polygonaceae Genus: Fagopyrum Species: F. esculentum Binomial name Fagopyrum esculentumMoench Synonyms[1] Polygonum fagopyrum L. 1753 Fagopyrum cereale Raf. Fagopyrum dryandrii Fenzl Fago...

 

IOF .30-06 sporting rifle

This article is missing information about need history and design details. Please expand the article to include this information. Further details may exist on the talk page. (February 2020) Bolt-action rifle IOF .30-06 sporting rifle IOF .30-06 Sporting Rifle with Nikon P223 3x 32 mm Riflescope mountedTypeBolt-action riflePlace of originIndiaProduction historyManufacturerRifle Factory IshaporeProduced2007[1]SpecificationsMass3.00 kg (6.61 lb)[2]Length1,125&...

 

Marcello Gamberini

Questa voce o sezione sull'argomento calciatori italiani non cita le fonti necessarie o quelle presenti sono insufficienti. Puoi migliorare questa voce aggiungendo citazioni da fonti attendibili secondo le linee guida sull'uso delle fonti. Segui i suggerimenti del progetto di riferimento. Questa voce sull'argomento calciatori italiani è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Marcello Gamber...

Aloysius Malo Ladi

Aloysius Malo Ladi Wakil Ketua Dewan Perwakilan Rakyat Daerah Provinsi Nusa Tenggara TimurPetahanaMulai menjabat 4 Oktober 2019PresidenJoko WidodoGubernurViktor Laiskodat Informasi pribadiLahir18 Januari 1973 (umur 51)Kupang, Nusa Tenggara TimurPartai politikPKBSuami/istriLosa Dasayani DanoAnak2Alma materUniversitas Katolik Widya Mandira KupangSunting kotak info • L • B Aloysius Malo Ladi, S.E. (lahir 18 Januari 1973) adalah politisi Partai Kebangkitan Bangsa yang menja...

 

Broad Margin

Historic house in South Carolina, United States United States historic placeBroad MarginU.S. National Register of Historic Places Broad Margin in Greenville, South Carolina ca. 1987Show map of South CarolinaShow map of the United StatesLocation9 West Avondale Drive, Greenville, South CarolinaCoordinates34°52′23″N 82°23′26″W / 34.87306°N 82.39056°W / 34.87306; -82.39056Area2 acres (0.81 ha)Built1954ArchitectFrank Lloyd WrightArchitectural styleUson...

 

Gentile Bargero

Questa voce sull'argomento calciatori italiani è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Gentile BargeroNazionalità Italia Calcio RuoloCentrocampista CarrieraSquadre di club1 1919-1925 Casale31+ (1+) 1 I due numeri indicano le presenze e le reti segnate, per le sole partite di campionato.Il simbolo → indica un trasferimento in prestito.   Modifica dati su Wikidata · Manual...

Parasite aircraft

Small plane aboard an airborne carrier This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Parasite aircraft – news · newspapers · books · scholar · JSTOR (June 2010) (Learn how and when to remove this message) An F-84 Thunderjet hooked on a FICON trapeze beneath its mother ship A parasite aircraft is a componen...

 

Bors (Tude-et-Lavalette)

BorscomuneBors – Veduta LocalizzazioneStato Francia Regione Nuova Aquitania Dipartimento Charente ArrondissementAngoulême CantoneTude-et-Lavalette TerritorioCoordinate45°20′35.16″N 0°10′01.92″E45°20′35.16″N, 0°10′01.92″E (Bors) Altitudine143 m s.l.m. Superficie15,72 km² Abitanti254[1] (2009) Densità16,16 ab./km² Altre informazioniCod. postale16190 Fuso orarioUTC+1 Codice INSEE16052 CartografiaBors Modifica dati su Wikidata �...