Pinacolborane

Pinacolborane
Names
	Preferred IUPAC name 4,4,5,5-Tetramethyl-1,3,2-dioxaborolane
	Other names HBpin
Identifiers
CAS Number	25015-63-8;
3D model (JSmol)	Interactive image;
ChemSpider	2016512;
ECHA InfoCard	100.118.700
EC Number	607-485-3;
PubChem CID	6364989;
CompTox Dashboard (EPA)	DTXSID30422852;
	InChI InChI=1S/C6H12BO2/c1-5(2)6(3,4)9-7-8-5/h1-4H3 Key: LZPWAYBEOJRFAX-UHFFFAOYSA-N;
	SMILES [B]1OC(C(O1)(C)C)(C)C;
Properties
Chemical formula	C6H13BO2
Molar mass	127.98 g·mol−1
Appearance	colorless liquid
Density	0.882 g/cm3
Boiling point	42–43 °C (108–109 °F; 315–316 K) 50 mmHg
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H220, H225, H260, H261, H315, H318
Precautionary statements	P210, P223, P231+P232, P233, P240, P241, P242, P243, P264, P280, P302+P352, P303+P361+P353, P305+P351+P338, P310, P321, P332+P313, P335+P334, P362, P370+P378, P377, P381, P402+P404, P403, P403+P235, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Pinacolborane is the borane with the formula (CH₃)₄C₂O₂BH. It features a boron hydride functional group incorporated in a five-membered C₂O₂B ring. Like related boron alkoxides, pinacolborane is monomeric. It is a colorless liquid.^[1] It features a reactive B-H functional group.^[2]

Use in organic synthesis

In the presence of catalysts, pinacolborane hydroborates alkenes and, less rapidly, alkynes.^[2]^[3]

Pinacolborane also effects catalyst-free hydroboration of aldehydes,^[4] ketones,^[5] and carboxylic acids.^[6]

Pinacolborane is used in borylation, a form of C-H activation.^[7]^[8]

Dehydrogenation of pinacolborane affords dipinacolatodiborane (B₂pin₂):^[9]

2 (CH₃)₄C₂O₂BH → (CH₃)₄C₂O₂B-BO₂C₂(CH₃)₄ + H₂

Related compounds

Catecholborane

References

^ Ramachandran, P. Veeraraghavan; Chandra, J. Subash; Ros, Abel; Fernández, Rosario; Lassaletta, José M.; Aggarwal, Varinder K.; Blair, Daniel J.; Myers, Eddie L. (2017). "Pinacolborane". Encyclopedia of Reagents for Organic Synthesis. pp. 1–12. doi:10.1002/047084289X.rn00574.pub3. ISBN 9780470842898.
^ ^a ^b Brown, H.C.; Zaidlewicz, M. (2001). Organic Syntheses Via Boranes, Vol. 2. Milwaukee, WI: Aldrich Chemical Co. ISBN 978-0-9708441-0-1.
^ Ely, Robert J.; Morken, James P. (2011). "Stereoselective Nickel-Catalyzed 1,4-Hydroboration of 1,3-Dienes". Organic Syntheses. 88: 342. doi:10.15227/orgsyn.088.0342.
^ Stachowiak, Hanna; Kaźmierczak, Joanna; Kuciński, Krzysztof; Hreczycho, Grzegorz (2018). "Catalyst-free and solvent-free hydroboration of aldehydes". Green Chemistry. 20 (8): 1738–1742. doi:10.1039/C8GC00042E. ISSN 1463-9262.
^ Wang, Weifan; Luo, Man; Yao, Weiwei; Ma, Mengtao; Pullarkat, Sumod A.; Xu, Li; Leung, Pak-Hing (2019). "Catalyst-free and solvent-free hydroboration of ketones". New Journal of Chemistry. 43 (27): 10744–10749. doi:10.1039/C9NJ02722J. ISSN 1144-0546.
^ Harinath, Adimulam; Bhattacharjee, Jayeeta; Panda, Tarun K. (2019). "Facile Reduction of carboxylic acids to primary alcohols under catalyst-free and solvent-free conditions". Chemical Communications. 55 (10): 1386–1389. doi:10.1039/C8CC08841A. ISSN 1359-7345. PMID 30607398.
^ Amaike, K.; Loach, R. P.; Movassaghi, M. (2015). "Direct C7 Functionalization of Tryptophan. Synthesis of Methyl (S)-2-((tert-Butoxycarbonyl)amino)-3-(7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indol-3-yl)propanoate". Organic Syntheses. 92: 373–385. doi:10.15227/orgsyn.092.0373 (inactive 31 May 2021). PMC 4733874. PMID 26839440.{{cite journal}}: CS1 maint: DOI inactive as of May 2021 (link)
^ Ishiyama, Tatsuo; Takagi, Jun; Nobuta, Yusuke; Miyaura, Norio (2005). "Iridium-Catalyzed C-H Borylation of Arenes and Heteroarenes: 1-Chloro-3-Iodo-5-(4,4,5,5-Tetramethyl-1,3,2-Dioxaborolan-2-Yl)Benzene and 2-(4,4,5,5,-Tetramethyl-1,3,2-Dioxaborolan-2-Yl)Indole". Organic Syntheses. 82: 126. doi:10.15227/orgsyn.082.0126. hdl:2115/56319.
^ Neeve, Emily C.; Geier, Stephen J.; Mkhalid, Ibraheem A. I.; Westcott, Stephen A.; Marder, Todd B. (2016). "Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse". Chemical Reviews. 116 (16): 9091–9161. doi:10.1021/acs.chemrev.6b00193. PMID 27434758.

[1] Ramachandran, P. Veeraraghavan; Chandra, J. Subash; Ros, Abel; Fernández, Rosario; Lassaletta, José M.; Aggarwal, Varinder K.; Blair, Daniel J.; Myers, Eddie L. (2017). "Pinacolborane". Encyclopedia of Reagents for Organic Synthesis. pp. 1–12. doi:10.1002/047084289X.rn00574.pub3. ISBN 9780470842898.

[HCC-2] Brown, H.C.; Zaidlewicz, M. (2001). Organic Syntheses Via Boranes, Vol. 2. Milwaukee, WI: Aldrich Chemical Co. ISBN 978-0-9708441-0-1.

[3] Ely, Robert J.; Morken, James P. (2011). "Stereoselective Nickel-Catalyzed 1,4-Hydroboration of 1,3-Dienes". Organic Syntheses. 88: 342. doi:10.15227/orgsyn.088.0342.

[4] Stachowiak, Hanna; Kaźmierczak, Joanna; Kuciński, Krzysztof; Hreczycho, Grzegorz (2018). "Catalyst-free and solvent-free hydroboration of aldehydes". Green Chemistry. 20 (8): 1738–1742. doi:10.1039/C8GC00042E. ISSN 1463-9262.

[5] Wang, Weifan; Luo, Man; Yao, Weiwei; Ma, Mengtao; Pullarkat, Sumod A.; Xu, Li; Leung, Pak-Hing (2019). "Catalyst-free and solvent-free hydroboration of ketones". New Journal of Chemistry. 43 (27): 10744–10749. doi:10.1039/C9NJ02722J. ISSN 1144-0546.

[6] Harinath, Adimulam; Bhattacharjee, Jayeeta; Panda, Tarun K. (2019). "Facile Reduction of carboxylic acids to primary alcohols under catalyst-free and solvent-free conditions". Chemical Communications. 55 (10): 1386–1389. doi:10.1039/C8CC08841A. ISSN 1359-7345. PMID 30607398.

[7] Amaike, K.; Loach, R. P.; Movassaghi, M. (2015). "Direct C7 Functionalization of Tryptophan. Synthesis of Methyl (S)-2-((tert-Butoxycarbonyl)amino)-3-(7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indol-3-yl)propanoate". Organic Syntheses. 92: 373–385. doi:10.15227/orgsyn.092.0373 (inactive 31 May 2021). PMC 4733874. PMID 26839440.{{cite journal}}: CS1 maint: DOI inactive as of May 2021 (link)

[8] Ishiyama, Tatsuo; Takagi, Jun; Nobuta, Yusuke; Miyaura, Norio (2005). "Iridium-Catalyzed C-H Borylation of Arenes and Heteroarenes: 1-Chloro-3-Iodo-5-(4,4,5,5-Tetramethyl-1,3,2-Dioxaborolan-2-Yl)Benzene and 2-(4,4,5,5,-Tetramethyl-1,3,2-Dioxaborolan-2-Yl)Indole". Organic Syntheses. 82: 126. doi:10.15227/orgsyn.082.0126. hdl:2115/56319.

[9] Neeve, Emily C.; Geier, Stephen J.; Mkhalid, Ibraheem A. I.; Westcott, Stephen A.; Marder, Todd B. (2016). "Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse". Chemical Reviews. 116 (16): 9091–9161. doi:10.1021/acs.chemrev.6b00193. PMID 27434758.

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