Abstract
The catalytic activity of a series of ruthenium complexes lacking cyclopentadienyl ligands has been evaluated for the cycloaddition of terminal alkynes and azides to give selectively 1,4-disubstituted 1,2,3-triazoles. The complex RuH(η 2-BH 4)(CO)(PCy 3) 2 was found to be an effective catalyst for the cycloaddition reactions. In the presence of RuH(η 2-BH 4)(CO)(PCy 3) 2, primary and secondary azides reacted with a range of terminal alkynes containing various functionalities to selectively produce 1,4-disubstituted 1,2,3-triazoles. The ruthenium-catalyzed azide-alkyne cycloaddition appears to proceed via a Ru-acetylide species as the key intermediate, which undergoes formal cycloaddition with an azide to give a ruthenium triazolide complex. The 1,4-disubstituted 1,2,3-triazole product is generated by metathesis of the triazolide complex with a terminal alkyne. In support of the reaction mechanism, the acetylide complex Ru(C≡CCMe 3) 2(CO)(PPh 3) 3 reacts cleanly with benzyl azide to give a ruthenium triazolide complex, which reacts with excess tert-butylacetylene in the presence of PPh 3 to give 4-tert-butyl-1-benzyl-1,2,3-triazole and the diacetylide complex Ru(C≡CCMe 3) 2(CO)(PPh 3) 3. The mechanism is also supported by DFT calculations.
| Original language | English |
|---|---|
| Pages (from-to) | 4904-4915 |
| Number of pages | 12 |
| Journal | Organometallics |
| Volume | 31 |
| Issue number | 13 |
| DOIs | |
| Publication status | Published - 9 Jul 2012 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Organic Chemistry
- Physical and Theoretical Chemistry
- Inorganic Chemistry
Cite this
Selective formation of 1,4-disubstituted triazoles from ruthenium-catalyzed cycloaddition of terminal alkynes and organic azides : Scope and reaction mechanism. / Liu, Pei Nian; Li, Juan; Su, Fu Hai; Ju, Kun Dong; Zhang, Li; Shi, Chuan; Sung, Herman H Y; Williams, Ian D.; Fokin, Valery V.; Lin, Zhenyang; Jia, Guochen.
In: Organometallics, Vol. 31, No. 13, 09.07.2012, p. 4904-4915.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Selective formation of 1,4-disubstituted triazoles from ruthenium-catalyzed cycloaddition of terminal alkynes and organic azides
T2 - Scope and reaction mechanism
AU - Liu, Pei Nian
AU - Li, Juan
AU - Su, Fu Hai
AU - Ju, Kun Dong
AU - Zhang, Li
AU - Shi, Chuan
AU - Sung, Herman H Y
AU - Williams, Ian D.
AU - Fokin, Valery V.
AU - Lin, Zhenyang
AU - Jia, Guochen
PY - 2012/7/9
Y1 - 2012/7/9
N2 - The catalytic activity of a series of ruthenium complexes lacking cyclopentadienyl ligands has been evaluated for the cycloaddition of terminal alkynes and azides to give selectively 1,4-disubstituted 1,2,3-triazoles. The complex RuH(η 2-BH 4)(CO)(PCy 3) 2 was found to be an effective catalyst for the cycloaddition reactions. In the presence of RuH(η 2-BH 4)(CO)(PCy 3) 2, primary and secondary azides reacted with a range of terminal alkynes containing various functionalities to selectively produce 1,4-disubstituted 1,2,3-triazoles. The ruthenium-catalyzed azide-alkyne cycloaddition appears to proceed via a Ru-acetylide species as the key intermediate, which undergoes formal cycloaddition with an azide to give a ruthenium triazolide complex. The 1,4-disubstituted 1,2,3-triazole product is generated by metathesis of the triazolide complex with a terminal alkyne. In support of the reaction mechanism, the acetylide complex Ru(C≡CCMe 3) 2(CO)(PPh 3) 3 reacts cleanly with benzyl azide to give a ruthenium triazolide complex, which reacts with excess tert-butylacetylene in the presence of PPh 3 to give 4-tert-butyl-1-benzyl-1,2,3-triazole and the diacetylide complex Ru(C≡CCMe 3) 2(CO)(PPh 3) 3. The mechanism is also supported by DFT calculations.
AB - The catalytic activity of a series of ruthenium complexes lacking cyclopentadienyl ligands has been evaluated for the cycloaddition of terminal alkynes and azides to give selectively 1,4-disubstituted 1,2,3-triazoles. The complex RuH(η 2-BH 4)(CO)(PCy 3) 2 was found to be an effective catalyst for the cycloaddition reactions. In the presence of RuH(η 2-BH 4)(CO)(PCy 3) 2, primary and secondary azides reacted with a range of terminal alkynes containing various functionalities to selectively produce 1,4-disubstituted 1,2,3-triazoles. The ruthenium-catalyzed azide-alkyne cycloaddition appears to proceed via a Ru-acetylide species as the key intermediate, which undergoes formal cycloaddition with an azide to give a ruthenium triazolide complex. The 1,4-disubstituted 1,2,3-triazole product is generated by metathesis of the triazolide complex with a terminal alkyne. In support of the reaction mechanism, the acetylide complex Ru(C≡CCMe 3) 2(CO)(PPh 3) 3 reacts cleanly with benzyl azide to give a ruthenium triazolide complex, which reacts with excess tert-butylacetylene in the presence of PPh 3 to give 4-tert-butyl-1-benzyl-1,2,3-triazole and the diacetylide complex Ru(C≡CCMe 3) 2(CO)(PPh 3) 3. The mechanism is also supported by DFT calculations.
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U2 - 10.1021/om300513w
DO - 10.1021/om300513w
M3 - Article
VL - 31
SP - 4904
EP - 4915
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 13
ER -