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]
Reaksiyaning stexiometriyasi:
- RS(O)CHR' 2 + Ac 2 O → RSC(OAc)R' 2 + AcOH
Sintetik amalga oshirish
tahrirAktivator 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]
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
tahrirPummererni 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.
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]
Oltingugurt o'rnida selen yordamida qayta tartibga solishni amalga oshirish mumkin.[9]
Pummererning parchalanishi
tahrirAgar 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:
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 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- ↑ de Lucchi, Ottorino. The Pummerer Reaction of Sulfinyl Compounds, 1991 — 157–184-bet. DOI:10.1002/0471264180.or040.03. ISBN 978-0471264187.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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 () - ↑ Pummerer, Rudolph (1909). „Über Phenyl-sulfoxyessigsäure“. Chemische Berichte. 42-jild, № 2. 2282–2291-bet. doi:10.1002/cber.190904202126.
- ↑ Pummerer, Rudolph (1910). „Über Phenylsulfoxy-essigsäure. (II.)“. Chemische Berichte. 43-jild, № 2. 1401–1412-bet. doi:10.1002/cber.19100430241.