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Juho Helaja

  • PL 55 (A. I. Virtasen aukio 1)

    00014

    Finland

20052020
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Publications 2005 2019

  • 31 Article
  • 1 Conference contribution
2019

Carbocatalytic Oxidative Dehydrogenative Couplings of (Hetero)Aryls by Oxidized Multi‐Walled Carbon Nanotubes in Liquid Phase

Wirtanen, T., Aikonen, S., Muuronen, M., Melchionna, M., Kemell, M., Davodi, F., Kallio, T., Hu, T. & Helaja, J., 29 Aug 2019, In : Chemistry: A European Journal. 25, 53, p. 12288–12293 7 p.

Research output: Contribution to journalArticleScientificpeer-review

Visible-Light-Photocatalyzed Reductions of N-Heterocyclic Nitroaryls to Anilines Utilizing Ascorbic Acid Reductant

Todorov, A., Aikonen, S. A. A., Muuronen, M. & Helaja, J., 8 May 2019, In : Organic Letters. 21, 10, p. 3764–3768 5 p.

Research output: Contribution to journalArticleScientificpeer-review

2017

Gold(I)-Catalyzed 1,3-O-Transposition of Ynones: Mechanism and Catalytic Acceleration with Electron-Rich Aldehydes

Aikonen, S., Muuronen, M., Wirtanen, T., Heikkinen, S., Musgreave, J., Burés, J. & Helaja, J., 20 Dec 2017, In : ACS catalysis. 8, 2, p. 960–967 8 p.

Research output: Contribution to journalArticleScientificpeer-review

Photoreductive Removal of O-Benzyl Groups from Oxyarene N-Heterocycles Assisted by O-Pyridine-pyridone Tautomerism

Todorov, A. R., Wirtanen, T. & Helaja, J., 15 Dec 2017, In : Journal of Organic Chemistry. 82, 24, p. 13756-13767 12 p.

Research output: Contribution to journalArticleScientificpeer-review

2016

Intermolecular oxidative dehydrogenative 3,3 '-coupling of benzo[b]furans and benzo[b]thiophenes promoted by DDQ/H+: total synthesis of shandougenine B

Wirtanen, T., Muuronen, M., Hurmalainen, J., Tuononen, H. M., Nieger, M. & Helaja, J., 2016, In : Organic Chemistry Frontiers. 3, 12, p. 1738-1745 8 p.

Research output: Contribution to journalArticleScientificpeer-review

Open Access
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2015

Carbocatalysed Oxidative C-sp2-C-sp2 Homocouplings of Benzo-Fused Heterocycles

Wirtanen, T., Mäkelä, M. K., Sarfraz, J., Ihalainen, P., Hietala, S., Melchionna, M. & Helaja, J., 16 Nov 2015, In : Advanced Synthesis & Catalysis. 357, 16-17, p. 3718-3726 9 p.

Research output: Contribution to journalArticleScientificpeer-review

Photoinduced Charge Transfer in a Conformational Switching Chlorin Dimer-Azafulleroid in Polar and Nonpolar Media

Nikkonen, T., Oliva, M. M., Kahnt, A., Muuronen, M., Helaja, J. & Guldi, D. M., 7 Jan 2015, In : Chemistry: A European Journal. 21, 2, p. 590-600 11 p.

Research output: Contribution to journalArticleScientificpeer-review

Synthesis, Aromaticity and Photophysical Behaviour of Ferrocene- and Ruthenocene-Appended Semisynthetic Chlorin Derivatives

Nikkonen, T., Oliva, M. M., Taubert, S., Melchionna, M., Kahnt, A. & Helaja, J., 1 Sep 2015, In : Chemistry: A European Journal. 21, 36, p. 12755-12768 14 p.

Research output: Contribution to journalArticleScientificpeer-review

2014

Effect of Mutual Position of Electron Donor and Acceptor on Photoinduced Electron Transfer in Supramolecular Chlorophyll-Fullerene Dyads

Stranius, K., Iashin, V., Nikkonen, T., Muuronen, M., Helaja, J. & Tkachenko, N., 27 Feb 2014, In : Journal of Physical Chemistry A. 118, 8, p. 1420-1429 10 p.

Research output: Contribution to journalArticleScientificpeer-review

Gold(III)-Catalyzed Enynamine-Cyclopentadiene Cycloisomerization with Chirality Transfer: An Experimental and Theoretical Study Indicating Involvement of Dual Au(III) Push-Pull Assisted cis-trans Isomerism

Wirtanen, T., Muuronen, M., Melchionna, M., Patzschke, M. & Helaja, J., 7 Nov 2014, In : Journal of Organic Chemistry. 79, 21, p. 10269-10283 15 p.

Research output: Contribution to journalArticleScientificpeer-review

Gold-Catalyzed Conversion of Aryl- and Alkyl-Substituted 1-(o-Aminophenyl)-2-propyn-1-ones to the Corresponding 2-Substituted 4-Quinolones

Seppänen, O., Muuronen, M. & Helaja, J., Jul 2014, In : European Journal of Organic Chemistry. 19, p. 4044-4052 9 p.

Research output: Contribution to journalArticleScientificpeer-review

Light-harvesting zinc chlorin-poly(4-vinylpyridine) complexes

Pale, V., Nikkonen, T., Helaja, J. & Tittonen, I., 1 Aug 2014, Proceedings of the 14th IEEE International Conference on Nanotechnology: Toronto, Canada, August 18-21, 2014. IEEE Computer Society, p. 225-228 4 p.

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Regioselectivity of Intermolecular Pauson-Khand Reaction of Aliphatic Alkynes: Experimental and Theoretical Study of the Effect of Alkyne Polarization

Fager-Jokela, E., Muuronen, M., Khaizourane, H., Vazquez-Romero, A., Verdaguer, X., Riera, A. & Helaja, J., 21 Nov 2014, In : Journal of Organic Chemistry. 79, 22, p. 10999-11010 12 p.

Research output: Contribution to journalArticleScientificpeer-review

2013

Biomimetic zinc chlorin-poly(4-vinylpyridine) assemblies: doping level dependent emission-absorption regimes

Pale, V., Nikkonen, T., Vapaavuori, J., Kostiainen, M., Kavakka, J., Selin, J., Tittonen, I. & Helaja, J., 2013, In : Journal of Materials Chemistry. C. 1, 11, p. 2166-2173 8 p.

Research output: Contribution to journalArticleScientificpeer-review

Open Access
File

Chlorophyll tailored 20-trifluoroacetamide and its azacrown derivative as pH sensitive colorimetric sensor probe with response to AcO-, F- and CN- ions

Iashin, V., Koso, T. V., Stranius, K., Muuronen, M., Heikkinen, S., Kavakka, J., Tkachenko, N. V. & Helaja, J., 2013, In : RSC Advances. 3, 29, p. 11485-11488 4 p.

Research output: Contribution to journalArticleScientificpeer-review

Open Access
File

Cycloisomerization of 2-Alkynylanilines to Indoles Catalyzed by Carbon-Supported Gold Nanoparticles and Subsequent Homocoupling to 3,3 '-Biindoles

Perea-Buceta, J. E., Wirtanen, T., Laukkanen, O-V., Mäkelä, M. K., Nieger, M., Melchionna, M., Huittinen, N., Lopez-Sanchez, J. A. & Helaja, J., 4 Nov 2013, In : Angewandte Chemie (International Edition). 52, 45, p. 11835-11839 5 p.

Research output: Contribution to journalArticleScientificpeer-review

Light-Harvesting Nanorods Based on Pheophorbide-Appending Cellulose

Sakakibara, K., Granström, M., Kilpeläinen, I., Helaja, J., Heinilehto, S., Inoue, R., Kanaya, T., Hill, J. P., Nakatsubo, F., Tsujii, Y. & Ariga, K., Sep 2013, In : Biomacromolecules. 14, 9, p. 3223-3230 8 p.

Research output: Contribution to journalArticleScientificpeer-review

2012

Cationic Gold Catalysis with Pyridine-Tethered Au(III) NHC-Carbenes: An Experimental and DFT Computational Study

Muuronen, M., Perea-Buceta, J. E., Nieger, M., Patzschke, M. & Helaja, J., 2012, In : Organometallics. 31, 11, p. 4320-4330 11 p.

Research output: Contribution to journalArticleScientificpeer-review

Electronic Regioselectivity of Diarylalkynes in Cobalt-Mediated Pauson-Khand Reaction: An Experimental and Computational Study with Para- and Meta-Substituted Diarylalkynes and Norbornene

Fager-Jokela, E., Muuronen, M., Patzschke, M. & Helaja, J., 19 Oct 2012, In : Journal of Organic Chemistry. 77, 20, p. 9134-9147 14 p.

Research output: Contribution to journalArticleScientificpeer-review

Tautomeric Switching and Metal-Cation Sensing of Ligand-Equipped 4-Hydroxy-/4-oxo-1,4-dihydroquinolines

Todorov, A. R., Nieger, M. & Helaja, J., 2012, In : Chemistry: A European Journal. 18, 23, p. 7269-7277 9 p.

Research output: Contribution to journalArticleScientificpeer-review

2010

Isolation of a Zwitterionic Dienegold(III) Complex Intermediate in the Direct Conversion of Enyne-Amines to Cyclopentadienes

Melchionna, M., Nieger, M. & Helaja, J., 2010, In : Chemistry: A European Journal. 16, 28, p. 8262-8267 6 p.

Research output: Contribution to journalArticleScientificpeer-review

β-Keto ester aminolysis of pheophorbide a methyl ester: a facile route for asymmetric chlorin ring substitution

Haavikko, R., Kavakka, J. S. & Helaja, J., 2010, In : Tetrahedron Letters. 51, 4, p. 714-716 3 p.

Research output: Contribution to journalArticleScientificpeer-review

2009

Hydrogen bond driven self-assembled C2-symmetric chlorin syn dimers; unorthodox models for chlorophyll special pairs in photosynthetic reaction centres

Nikkonen, T., Haavikko, R. & Helaja, J. P., 2009, In : Organic & Biomolecular Chemistry. 7, p. 2046-2052 7 p.

Research output: Contribution to journalArticleScientificpeer-review

Zn pyro-pheophorbide a-fulleronicotine dyad; supramolecular self assembled donor-acceptor system for photoinduced charge separation

Kavakka, J. S., Heikkinen, S., Kilpeläinen, I., Tkachenko, N. V. & Helaja, J., 2009, In : Chemical Communications. 2009, 7, p. 758-760 3 p.

Research output: Contribution to journalArticleScientificpeer-review

2008

Development of intermolecular additive free Pauson-Khand reactions for estrone E-ring extension using microwaves

Fager-Jokela, E., Kaasalainen, E., Leppänen, K. & Helaja, J., 2008, In : Tetrahedron. 64, p. 10381-10387 7 p.

Research output: Contribution to journalArticleScientificpeer-review

Tosylation and acylation of cellulose in 1-allyl-3-methylimidazolium chloride

Granström, M., Kavakka, J., King, A., Majoinen, J., Mäkelä, V., Helaja, J., Hietala, S., Virtanen, T., Maunu, S-L., Argyropoulos, D. S. & Kilpeläinen, I., 2008, In : Cellulose. 15, 3, p. 481-488 8 p.

Research output: Contribution to journalArticleScientificpeer-review

Zn pyropheophorbide a: a ß-face selective nicotine receptor

Kavakka, J. S., Heikkinen, S. & Helaja, J., 2008, In : European Journal of Organic Chemistry. p. 4932-4937 6 p.

Research output: Contribution to journalArticleScientificpeer-review

2007

Noncovalent attachment of pyro-pheophorbide a to a carbon nanotube

Kavakka, J. S., Heikkinen, S., Kilpeläinen, I., Mattila, M., Lipsanen, H. & Helaja, J., 2007, In : Chemical Communications. 6, p. 519-521 3 p.

Research output: Contribution to journalArticleScientificpeer-review

2006

Development of Dpa-based imidazole zinc anion receptors

Salo, T. M., Helaja, J. & Koskinen, A. M. P., 2006, In : Tetrahedron Letters. 47, p. 2977-2980 4 p.

Research output: Contribution to journalArticleScientificpeer-review

E-Ring extended estrone derivatives: introduction of 2-phenylcyclopentenone to the estrone D-ring via an intermolecular Pauson-Khand reaction

Kaasalainen, E., Tois, J., Russo, L., Rissanen, K. & Helaja, J., 2006, In : Tetrahedron Letters. 47, p. 5669-5672 4 p.

Research output: Contribution to journalArticleScientificpeer-review

Novel crown ether and salen metal chelation driven molecular pincers

Abe, A. M. M., Helaja, J. & Koskinen, A. M. P., 2006, In : Organic Letters. 8, p. 4537-4540 4 p.

Research output: Contribution to journalArticleScientificpeer-review

2005

Locked conformations for proline pyrrolidine ring: Synthesis and conformational analysis of cis- and trans-4-tert-butylprolines

Koskinen, A. M. P., Helaja, J., Kumpulainen, E. T. T., Koivisto, J., Mansikkamaki, H. & Rissanen, K., 2005, In : Journal of Organic Chemistry. 70, p. 6447-6453 7 p.

Research output: Contribution to journalArticleScientificpeer-review