| 1. |
- Bengtson, A, et al.
(författare)
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Fast synthesis of aryl triflates with controlled microwave heating
- 2002
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Ingår i: Organic Letters. - Uppsala Univ, Dept Organ Pharmaceut Chem, BMC, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 4:7, s. 1231-1233
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Tidskriftsartikel (refereegranskat)abstract
- [GRAPHICS] Synthesis of aryl triflates from phenols using N-phenyltriflimide requires only 6 min for completion when conducted with controlled microwave heating. The methodology was applied to both solution- and solid-phase conditions. Ten different aryl triflates were synthesized and isolated in good yields. Applications in high-throughput chemistry are suggested.
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| 2. |
- Bengtson, A, et al.
(författare)
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Protected indanones by a Heck-Aldol annulation reaction
- 2002
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 67:16, s. 5854-5856
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Tidskriftsartikel (refereegranskat)abstract
- Monoprotected 3-hydroxyindan-1-ones have been prepared in moderate to good yields by a new tandem reaction involving salicylaldehyde triflates and commercially available 2-hydroxyethyl vinyl ether. This one-pot annulation reaction proceeds in the presence of a palladium bidentate catalyst and results in the formation of two new ring systems.
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| 3. |
- Vallin, K S A, et al.
(författare)
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A new regioselective Heck vinylation with enamides. Synthesis and investigation of fluorous-tagged bidentate ligands for fast separation
- 2003
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, BMC, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 68:17, s. 6639-6645
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Tidskriftsartikel (refereegranskat)abstract
- Internal ligand-controlled Heck vinylations of enamides were performed with high regioselectivity and delivered moderate to good yields of dienamides. Controlled heating by microwave irradiation accelerated the palladium-catalyzed reactions, and full conversions were achieved after reaction times of only 15-30 min. New bidentate fluorous-tagged 1,3-bis(diphenylphosphino)propane ligands (F-dppp's) were synthesized and examined. The cationic vinylations of the enamides with F-dppp ligands rendered essentially the same alpha-selectivity and catalytic activity as in those vinylations where nonfluorous ligands were employed. After reaction, the fluorous-tagged ligand material was easily removed by convenient solid fluorous phase separation. The high selectivity, simplicity, and generality of the experimental procedure should make this approach to 2-acylamino-1,3-butadienes attractive.
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| 4. |
- Vallin, K S A, et al.
(författare)
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Aqueous DMF-potassium carbonate as a substitute for thallium and silver additives in the palladium-catalyzed conversion of aryl bromides to acetyl arenes
- 2001
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, Dept Organ Pharmaceut Chem, BMC, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 66:12, s. 4340-4343
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Tidskriftsartikel (refereegranskat)abstract
- Highly selective palladium-catalyzed internal alpha -arylations of alkyl vinyl ethers with aryl and heteroaryl bromides were conveniently conducted in aqueous DMF with potassium carbonate as base and with DPPP as bidentate ligand. The corresponding acetyl arene products were, after hydrolysis, isolated in good to excellent yields. This Heck reaction procedure does not require toxic thallium or expensive silver salt additives, is promoted by water, and is suggested to proceed via charged organopalladium intermediates. Single-mode microwave irradiation was utilized in one example to shorten the reaction time.
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| 5. |
- Vallin, K S A, et al.
(författare)
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High-speed Heck reactions in ionic liquid with controlled microwave heating
- 2002
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, BMC, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 67:17, s. 6243-6246
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Tidskriftsartikel (refereegranskat)abstract
- Palladium-catalyzed Heck arylations in the polar and robust ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6)), have for the first time been accomplished under microwave irradiation. The couplings were efficiently performed in sealed tubes within 5-45 min of heating. Without significant reductions in yield, a phosphine-free ionic catalyst phase could be recycled in five successive 20 min reactions at 180 degreesC. The product was easily removed from the reaction medium by distillation.
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| 6. |
- Vallin, K S A, et al.
(författare)
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Highly selective palladium-catalyzed synthesis of protected alpha,beta-unsaturated methyl ketones and 2-alkoxy-1,3-butadienes. High-speed chemistry by microwave flash heating
- 2000
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, Uppsala Biomed Ctr, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 65:15, s. 4537-4542
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Tidskriftsartikel (refereegranskat)abstract
- A selective and mild procedure is described for the direct synthesis of 2-alkene-2-methyl-1,3-dioxolanes via regiocontrolled Heck vinylation of commercially available 2-hydroxyethyl vinyl ether. The procedure permits chemoselective transformation of a vinylic triflate or bromide into a blocked alpha,beta-unsaturated methyl ketone. Furthermore, a significantly improved and highly regioselective synthesis of 2-alkoxy-1,3-butadienes has been developed. Flash heating by microwave irradiation promotes the palladium-catalyzed reactions, and the starting materials are fully converted after reaction times of 5-7 min.
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| 7. |
- Belda, O., et al.
(författare)
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Highly stereo- and regioselective allylations catalyzed by Mo-pyridylamide complexes : Electronic and steric effects of the ligand
- 2000
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, Uppsala Biomed Ctr, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. Royal Inst Technol, Dept Chem, SE-10044 Stockholm, Sweden. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 65:18, s. 5868-5870
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Tidskriftsartikel (refereegranskat)
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| 8. |
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| 9. |
- Bremberg, U, et al.
(författare)
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Rapid and stereoselective C-C, C-O, C-N and C-S couplings via microwave accelerated palladium-catalyzed allylic substitutions
- 2000
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Ingår i: Synthesis (Stuttgart). - Uppsala Univ, Uppsala Biomed Ctr, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. Royal Inst Technol, Dept Chem, SE-10044 Stockholm, Sweden.. - 0039-7881 .- 1437-210X. ; :7, s. 1004-1008
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Tidskriftsartikel (refereegranskat)abstract
- Palladium-catalyzed substitution of cyclohex-2-en-1-yl ethyl carbonate with neutral C-, O-, and N-nucleophiles was achieved in 1-2 minutes using microwave flash hearing. Enantioselectivities up to 96% were observed. Ionic nucleophiles tended to result in lower ee. With S-nucleophiles problems with the stability of the nucleophile were encountered.
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| 10. |
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