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Pummererning qayta olinishi

 

Pummererning qayta tashkil etilishi organik reaksiya bo'lib, alkil sulfoksid sirka angidrid ishtirokida a- atsiloksi - tioeter (mono- tioatsetal -ester) ga aylanadi.[1][2][3]

Pummererni qayta tashkil etish
Pummererni qayta tashkil etish

Reaksiyaning stexiometriyasi:

RS(O)CHR' 2 + Ac 2 O → RSC(OAc)R' 2 + AcOH

Sintetik amalga oshirish tahrir

Aktivator sifatida sirka angidrididan tashqari, trifloroasetik angidrid va triflorometansülfonik angidrid ishlatilgan.[4] Asetatlardan tashqari umumiy nukleofillar arenlar, alkenlar, amidlar va fenollardir.

TiCl <sub id="mwJw">4</sub> va SnCl <sub id="mwKQ">4</sub> kabi a-atsil sulfoksidlar va Lyuis kislotalaridan foydalanish reaksiyani past haroratlarda davom ettirishga imkon beradi (0 °C).[5]

Tionilxlorid sirka angidrid o'rniga elektrofil oraliq hosil bo'lishini yo'q qilish va xloridni nukleofil sifatida etkazib berish uchun a-xloro-tioefirni berish uchun ishlatilishi mumkin:[6]

 
Tionilxlorid yordamida Pummererni qayta tartibga solishga misol

Boshqa angidridlar va asil galogenidlar shunga o'xshash mahsulotlarni berishi mumkin. Bu reaksiyani noorganik kislotalar ham berishi mumkin. Ushbu mahsulot gidroliz orqali aldegid yoki ketonga aylantirilishi mumkin.[7]

Mexanizm tahrir

Pummererni qayta tashkil etish mexanizmi sulfoksidni (1 va 2 - rezonans tuzilmalari) sirka angidrid bilan 3 ni hosil qilish uchun asetat bilan astillanishi bilan boshlanadi. Keyin asetat qo'shimcha mahsulot sifatida sirka kislotasi bilan katyoniktial tuzilmani 4 hosil qilish uchun eliminatsiya reaksiyasini qo'zg'atish uchun katalizator vazifasini bajaradi. Nihoyat, asetat tialga hujum qilib, yakuniy mahsulot 5 ni beradi.

 
Pummererni qayta tashkil etish mexanizmi

Faollashtirilgan tial elektrofil turli xil molekulyar va molekulalararo nukleofillar tomonidan uglerod-uglerod va uglerod -geteroatom aloqalarini hosil qilish uchun tutilishi mumkin.

Oraliq mahsulot shu qadar elektrofilki, hatto neytral nukleofillar ham, jumladan 1,3-benzodioksol kabi elektron beruvchi guruhlarga ega aromatik halqalardan ham foydalanish mumkin:[8]

 
Veratrol yordamida Pummererni qayta tartibga solishga misol

Oltingugurt o'rnida selen yordamida qayta tartibga solishni amalga oshirish mumkin.[9]

Pummererning parchalanishi tahrir

Agar   holatidagi o'rinbosar barqaror karbokatsiya hosil qilsa, oraliq bosqichda  -vodorod atomi emas, balki bu guruh yo'q qilinadi. Bu o'zgarish Pummerer parchalanishi deb ataladi.[10] Ushbu reaksiya turi quyida sulfoksidlar va trifloroasetik angidrid (TFAA) to'plami bilan ko'rsatilgan:

 
Pummererning parchalanishi

Pastki o'ngdagi yuqoridagi diagrammada ko'rsatilgan "R2" organik guruhi metil binafsha karboksidir, uning pK R + 9,4 ga teng H + ni yo'qotish bilan raqobatlasha olmaydi va shuning uchun klassik Pummerer qayta tashkil etilishi sodir bo'ladi. Chapdagi reaksiya parchalanishdir, chunki pK R+ = 23,7 bo'lgan chiqib ketish guruhi ayniqsa barqaror.

Reaksiya Rudolf Pummerer [de] tomonidan kashf etilgan, bu haqda 1909-yilda xabar bergan[11][12]

Yana qarang tahrir

  • Organosulfur kimyosi
  • Polonovskiy reaksiyasi - amin oksidi ishtirokidagi shunga o'xshash reaksiya
  • Boekelheid reaksiyasi - piridin oksidi ishtirokidagi shunga o'xshash reaksiya

Manbalar tahrir

  1. ↑ de Lucchi, Ottorino. The Pummerer Reaction of Sulfinyl Compounds, 1991 — 157–184 bet. DOI:10.1002/0471264180.or040.03. ISBN 978-0471264187. 
  2. ↑ Padwa, Albert; Gunn, David E., Jr.; Osterhout, Martin H. (1997). „Application of the Pummerer Reaction Toward the Synthesis of Complex Carbocycles and Heterocycles“. Synthesis. 1997-jild, № 12. 1353–1377-bet. doi:10.1055/s-1997-1384.
  3. ↑ Padwa, Albert; Bur, Scott K.; Danca, Diana M.; Ginn, John D.; Lynch, Stephen M. (2002). „Linked Pummerer-Mannich Ion Cyclizations for Heterocyclic Chemistry“. Synlett. 2002-jild, № 6. 851–862-bet. doi:10.1055/s-2002-31891.
  4. ↑ Smith, Laura H. S.; Coote, Susannah C.; Sneddon, Helen F.; Procter, David J. (2010). „Beyond the Pummerer Reaction: Recent Developments in Thionium Ion Chemistry“. Angewandte Chemie International Edition. 49-jild, № 34. 5832–44-bet. doi:10.1002/anie.201000517. PMID 20583014.
  5. ↑ Stamos, Ioannis K. (1986). „Arylation of α-phosphoryl sulfides via their pummerer rearrangement intermediates generated from the corresponding sulfoxides“. Tetrahedron Letters. 27-jild, № 51. 6261–6262-bet. doi:10.1016/S0040-4039(00)85447-7.
  6. ↑ Kosugi, Hiroshi; Watanabe, Yasuyuki; Uda, Hisashi (1989). „Lewis Acid-Mediated Carbon-Carbon bond forming reaction using the Pummerer Rearrangement Products from Chiral beta-Hydroxy Sulfoxides“. Chemistry Letters. 18-jild, № 10. 1865–1868-bet. doi:10.1246/cl.1989.1865.
  7. ↑ Meffre, Patrick; Durand, Philippe; Le Goffic, François (1999). „Methyl (S)-2-phthalimido-4-methylthiobutanoate“. Organic Syntheses. 76-jild. 123-bet. doi:10.15227/orgsyn.076.0123.
  8. ↑ Ishibashi, Hiroyuki; Miki, Yumiko; Ikeda, Yoshiaki; Kiriyama, Akiko; Ikeda, Masazumi (1989). „Synthesis of α-(Methylthio)arylacetamides and Their Conversion into Some Biologically Active Arylethylamines“. Biological & Pharmaceutical Bulletin. 37-jild, № 12. 3396–3398-bet. doi:10.1248/cpb.37.3396.
  9. ↑ Gilmour, Ryan; Prior, Timothy J.; Burton, Jonathan W.; Holmes, Andrew B. (2007). „An organocatalytic approach to the core of eunicellin“. Chemical Communications. № 38. 3954–6-bet. doi:10.1039/B709322E. PMID 17896044.
  10. ↑ Laleu, Benoît; Santarém Machado, Marco; Lacour, Jérôme (25–may 2006–yil). „Pummerer fragmentation vs. Pummerer rearrangement: a mechanistic analysis“. Chemical Communications. № 26. 2786–2788-bet. doi:10.1039/b605187a. PMID 17009463.{{cite magazine}}: CS1 maint: date format ()
  11. ↑ Pummerer, Rudolph (1909). „Über Phenyl-sulfoxyessigsäure“. Chemische Berichte. 42-jild, № 2. 2282–2291-bet. doi:10.1002/cber.190904202126.
  12. ↑ Pummerer, Rudolph (1910). „Über Phenylsulfoxy-essigsäure. (II.)“. Chemische Berichte. 43-jild, № 2. 1401–1412-bet. doi:10.1002/cber.19100430241. 
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