Hafnium Trifluoromethanesulfonate

Hafnium(IV) Triflate
Names
	IUPAC names Hafnium(IV) trifluoromethanesulfonate;
Identifiers
CAS Number	161337-67-3 ;
3D model (JSmol)	Interactive image;
ChemSpider	21170913;
EC Number	624-948-5;
PubChem CID	9853707;
	InChI InChI=1S/4CHF3O3S.Hf/c42-1(3,4)8(5,6)7;/h4(H,5,6,7);/q;;;;+4/p-4 Key: BQYMOILRPDTPPJ-UHFFFAOYSA-J;
	SMILES C(F)(F)(F)S(=O)(=O)[O-].C(F)(F)(F)S(=O)(=O)[O-].C(F)(F)(F)S(=O)(=O)[O-].C(F)(F)(F)S(=O)(=O)[O-].[Hf+4];
Properties
Chemical formula	Hf(OTf)4
Molar mass	774.8 g/mol
Appearance	Colourless solid
Melting point	350 °C (662 °F; 623 K)
Hazards
Main hazards	irritantant
Safety data sheet	[1]
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H314, H315, H318, H319, H335
GHS precautionary statements	P261, P264, P271, P280, P302+352, P304+340, P305+351+338, P312, P321, P332+313, P337+313, P362, P403+233, P405, P501
Flash point	Non-flammable
Related compounds
Other anions	Hafnium tetrachloride; Hafnium tetrafluoride; Hafnium(IV) bromide; Hafnium(IV) iodide
Other cations	Titanium(IV) triflate; Zirconium(IV) triflate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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	Infobox references

Hafnium(IV) triflate or hafnium trifluoromethansulfonate is an inorganic substance with the idealized formula Hf(OSO₂CF₃)₄, also written as Hf(OTf)₄. Hafnium triflate is used as an impure mixture as a catalyst. Hafnium (IV) has an ionic radius of intermediate range (Al < Ti < Hf < Zr < Sc < Ln) and has an oxophilic hard character typical of group IV metals. This solid is a stronger Lewis acid than its typical precursor hafnium tetrachloride, HfCl₄, because of the strong electron-withdrawing nature of the four triflate groups, which makes it a great Lewis acid and has many uses including as a great catalyst at low Lewis acid loadings for electrophilic aromatic substitution and nucleophilic substitution reactions.^[1]

Preparation

The compound was first synthesized by the Kobayashi group in 1995 via the reaction of HfCl₄ and triflic acid.^[2] This solid is air stable, easy to handle, and commercially available.^[3]

Uses

Electrophilic Substitutions

Hf(OTf)₄ catalyzed Friedel-Craft acylation and alkylation reactions

Friedel-Craft acylation or alkylation reactions are some of the most important synthetic methodologies to introduce carbonyl or alkyl groups onto aromatic compounds.^[4] The first Hf(OTf)₄ catalyzed Friedel-Crafts acylation was developed by Kobayashi et al. in 1995.^[2]^[5] The authors demonstrated that Friedel-Crafts acylation could be achieved in excellent yield between arenes and acid anhydrides when utilizing Hf(OTf)₄ as a catalyst. Hf(OTf)₄, was the most effective in comparison to other Lewis acids including BF₃ • OEt₂, Sc(OTf)₃, and Zr(OTf)₄. Similalrly, Hf(OTf)₄ shows excellent activity in Friedel-Crafts alkylation’s, and enabled the alkylation of benzene with benzylic and tertiary alkyl chlorides.

Hf(OTf)₄-catalyzed Friedel-Crafts alkylation has been utilized in the total synthesis of the altertoxin III framework. This approach provided a more efficient synthesis of the fused-ring structure compared to previous methods.^[6]

Hf(OTf)₄ mediated synthesis of altertoxins

Hf(OTf)₄, alongside Sc(OTf)₃ and In(OTf)₃, has been shown to activate alkynes and enable electrophilic substitution. In 2004 Song and Lee et al. reported Hf(OTf)₄-catalyzed Friedel-Crafts alkenylation of benzene with alkenyl derivatives.^[7]

Hf(OTf)₄ enabled electrophilic substitution of alkynes

Nucleophilic Substitutions

In 2008, Zhu et al. demonstrated that Hf(OTf)₄ was an effective catalyst for the thioacetalization of aldehydes and ketones.^[8] In the absence of Lewis acid this reaction can occur in glycerol at 90 °C. Hf(OTf)₄ accelerated the reaction rate under milder conditions with only 0.1 mol% catalyst loading. For example, Hf(OTf)₄ catalyzes the reaction between benzaldehyde and 2.0 equiv. of either ethanethiol or 1.0 equiv. of propane-1,3,-dithiol readily in quantitative yield.

Hf(OTf)₄ catalyzed thioacetalization of benzaldehyde

This methodology was utilized in the total synthesis of (-)-leucomidine B from an enantioenriched monoacid synthesized via a Hf(OTf)₄ catalyzed thioacetalization.^[9]

Total synthesis of (-)-leucomidine B

In 2009, Nakamura et al. demonstrated that Hf(OTf)₄ was uniquely able to catalyzed a Prins reaction between an aryl aldehyde and an O-protected/unprotected cyclohex-3-ene-1,2-dimethanol.^[10]

Hf(OTf)₄ catalyzed Prins cyclization

References

↑ Ishitani, Haruro; Suzuki, Hirotsugu; Saito, Yuki; Yamashita, Yasuhiro; Kobayashi, Shū (2015). "Hafnium Trifluoromethanesulfonate [Hf(OTf)4 as a Unique Lewis Acid in Organic Synthesis"] (in en). European Journal of Organic Chemistry 2015 (25): 5485–5499. doi:10.1002/ejoc.201500423. ISSN 1099-0690. https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/ejoc.201500423.
↑ ^2.0 ^2.1 Hachiya, Iwao; Moriwaki, Mitsuhiro; Kobayashi, Shu (1995-07-01). "Hafnium(IV) Trifluoromethanesulfonate, An Efficient Catalyst for the Friedel–Crafts Acylation and Alkylation Reactions". Bulletin of the Chemical Society of Japan 68 (7): 2053–2060. doi:10.1246/bcsj.68.2053. ISSN 0009-2673. https://www.journal.csj.jp/doi/10.1246/bcsj.68.2053.
↑ Li, Zhiya; Plancq, Baptiste; Ollevier, Thierry (2011) (in en), Hafnium(IV) Trifluoromethanesulfonate, American Cancer Society, doi:10.1002/047084289x.rn01315, ISBN 978-0-470-84289-8, https://onlinelibrary.wiley.com/doi/abs/10.1002/047084289X.rn01315, retrieved 2021-06-12
↑ Calloway, N. O. (1935-12-01). "The Friedel-Crafts Syntheses.". Chemical Reviews 17 (3): 327–392. doi:10.1021/cr60058a002. ISSN 0009-2665. https://doi.org/10.1021/cr60058a002.
↑ Hachiya, Iwao; Moriwaki, Mitsuhiro; Kobayashi, Shu (1995-01-16). "Catalytic Friedel-Crafts acylation reactions using hafnium triflate as a catalyst in lithium perchlorate-nitromethane" (in en). Tetrahedron Letters 36 (3): 409–412. doi:10.1016/0040-4039(94)02221-V. ISSN 0040-4039. https://www.sciencedirect.com/science/article/abs/pii/004040399402221V.
↑ Geiseler, Oliver; Müller, Monika; Podlech, Joachim (2013-05-06). "Synthesis of the altertoxin III framework" (in en). Tetrahedron 69 (18): 3683–3689. doi:10.1016/j.tet.2013.03.013. ISSN 0040-4020. https://www.sciencedirect.com/science/article/abs/pii/S0040402013003633.
↑ Song, Choong Eui; Jung, Da-un; Choung, Su Yhen; Roh, Eun Joo; Lee, Sang-gi (2004). "Dramatic Enhancement of Catalytic Activity in an Ionic Liquid: Highly Practical Friedel–Crafts Alkenylation of Arenes with Alkynes Catalyzed by Metal Triflates". Angewandte Chemie International Edition 43 (45): 6183–6185. doi:10.1002/anie.200460292. ISSN 1521-3773. PMID 15549737. https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200460292.
↑ Wu, Yan-Chao; Zhu, Jieping (2008-12-05). "Hafnium Trifluoromethanesulfonate (Hafnium Triflate) as a Highly Efficient Catalyst for Chemoselective Thioacetalization and Transthioacetalization of Carbonyl Compounds". The Journal of Organic Chemistry 73 (23): 9522–9524. doi:10.1021/jo8021988. ISSN 0022-3263. PMID 18991383. https://doi.org/10.1021/jo8021988.
↑ Gualtierotti, Jean-Baptiste; Pasche, Delphine; Wang, Qian; Zhu, Jieping (2014). "Phosphoric Acid Catalyzed Desymmetrization of Bicyclic Bislactones Bearing an All-Carbon Stereogenic Center: Total Syntheses of (−)-Rhazinilam and (−)-Leucomidine B" (in en). Angewandte Chemie International Edition 53 (37): 9926–9930. doi:10.1002/anie.201405842. ISSN 1521-3773. PMID 25048385. https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201405842.
↑ Nakamura, Masayuki; Niiyama, Kenji; Yamakawa, Takeru (2009-11-25). "Versatile method for the synthesis of 4-substituted 6-methyl-3-oxabicyclo[3.3.1non-6-ene-1-methanol derivatives: Prins-type cyclization reaction catalyzed by hafnium triflate"] (in en). Tetrahedron Letters 50 (47): 6462–6465. doi:10.1016/j.tetlet.2009.08.120. ISSN 0040-4039. https://www.sciencedirect.com/science/article/abs/pii/S0040403909016943.

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Original source: https://en.wikipedia.org/wiki/Hafnium trifluoromethanesulfonate. Read more

[1] Ishitani, Haruro; Suzuki, Hirotsugu; Saito, Yuki; Yamashita, Yasuhiro; Kobayashi, Shū (2015). "Hafnium Trifluoromethanesulfonate [Hf(OTf)4 as a Unique Lewis Acid in Organic Synthesis"] (in en). European Journal of Organic Chemistry 2015 (25): 5485–5499. doi:10.1002/ejoc.201500423. ISSN 1099-0690. https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/ejoc.201500423.

[:0-2] 2.0 ^2.1 Hachiya, Iwao; Moriwaki, Mitsuhiro; Kobayashi, Shu (1995-07-01). "Hafnium(IV) Trifluoromethanesulfonate, An Efficient Catalyst for the Friedel–Crafts Acylation and Alkylation Reactions". Bulletin of the Chemical Society of Japan 68 (7): 2053–2060. doi:10.1246/bcsj.68.2053. ISSN 0009-2673. https://www.journal.csj.jp/doi/10.1246/bcsj.68.2053.

[3] Li, Zhiya; Plancq, Baptiste; Ollevier, Thierry (2011) (in en), Hafnium(IV) Trifluoromethanesulfonate, American Cancer Society, doi:10.1002/047084289x.rn01315, ISBN 978-0-470-84289-8, https://onlinelibrary.wiley.com/doi/abs/10.1002/047084289X.rn01315, retrieved 2021-06-12

[4] Calloway, N. O. (1935-12-01). "The Friedel-Crafts Syntheses.". Chemical Reviews 17 (3): 327–392. doi:10.1021/cr60058a002. ISSN 0009-2665. https://doi.org/10.1021/cr60058a002.

[5] Hachiya, Iwao; Moriwaki, Mitsuhiro; Kobayashi, Shu (1995-01-16). "Catalytic Friedel-Crafts acylation reactions using hafnium triflate as a catalyst in lithium perchlorate-nitromethane" (in en). Tetrahedron Letters 36 (3): 409–412. doi:10.1016/0040-4039(94)02221-V. ISSN 0040-4039. https://www.sciencedirect.com/science/article/abs/pii/004040399402221V.

[6] Geiseler, Oliver; Müller, Monika; Podlech, Joachim (2013-05-06). "Synthesis of the altertoxin III framework" (in en). Tetrahedron 69 (18): 3683–3689. doi:10.1016/j.tet.2013.03.013. ISSN 0040-4020. https://www.sciencedirect.com/science/article/abs/pii/S0040402013003633.

[7] Song, Choong Eui; Jung, Da-un; Choung, Su Yhen; Roh, Eun Joo; Lee, Sang-gi (2004). "Dramatic Enhancement of Catalytic Activity in an Ionic Liquid: Highly Practical Friedel–Crafts Alkenylation of Arenes with Alkynes Catalyzed by Metal Triflates". Angewandte Chemie International Edition 43 (45): 6183–6185. doi:10.1002/anie.200460292. ISSN 1521-3773. PMID 15549737. https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200460292.

[8] Wu, Yan-Chao; Zhu, Jieping (2008-12-05). "Hafnium Trifluoromethanesulfonate (Hafnium Triflate) as a Highly Efficient Catalyst for Chemoselective Thioacetalization and Transthioacetalization of Carbonyl Compounds". The Journal of Organic Chemistry 73 (23): 9522–9524. doi:10.1021/jo8021988. ISSN 0022-3263. PMID 18991383. https://doi.org/10.1021/jo8021988.

[9] Gualtierotti, Jean-Baptiste; Pasche, Delphine; Wang, Qian; Zhu, Jieping (2014). "Phosphoric Acid Catalyzed Desymmetrization of Bicyclic Bislactones Bearing an All-Carbon Stereogenic Center: Total Syntheses of (−)-Rhazinilam and (−)-Leucomidine B" (in en). Angewandte Chemie International Edition 53 (37): 9926–9930. doi:10.1002/anie.201405842. ISSN 1521-3773. PMID 25048385. https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201405842.

[10] Nakamura, Masayuki; Niiyama, Kenji; Yamakawa, Takeru (2009-11-25). "Versatile method for the synthesis of 4-substituted 6-methyl-3-oxabicyclo[3.3.1non-6-ene-1-methanol derivatives: Prins-type cyclization reaction catalyzed by hafnium triflate"] (in en). Tetrahedron Letters 50 (47): 6462–6465. doi:10.1016/j.tetlet.2009.08.120. ISSN 0040-4039. https://www.sciencedirect.com/science/article/abs/pii/S0040403909016943.