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			{{Redirect|Superhydride|the class of compounds sometimes known as superhydrides|Polyhydride}}{{chembox
	{{chembox
			|Watchedfields = changed
	| verifiedrevid = 400493914
			|verifiedrevid = 415897994
	| Name = Lithium triethylborohydride
			|Name = Lithium triethylborohydride
	| ImageFile = Lithiumtriethylborohydride.svg
	| IUPACName = Lithium triethylborohydride		|ImageFile = Lithium triethylborohydride Structural Formula V1.svg
			|ImageAlt = Skeletal formula of lithium triethylborohydride
	| OtherNames = Superhydride<br />LiTEBH
			|PIN = Lithium triethylboranuide
	| Section1 = {{Chembox Identifiers
			|OtherNames = Superhydride<br />LiTEBH
	| CASNo = 22560-16-3
			|Section1={{Chembox Identifiers
	| PubChem = 2723993
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}		|CASNo_Ref = {{cascite|correct|??}}
			|CASNo = 22560-16-3
	| ChemSpiderID = 2006168
			|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| SMILES = .CC(CC)CC
			|ChemSpiderID = 2006168
	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
			|EC_number = 245-076-8
	| StdInChI = 1S/C6H16B.Li/c1-4-7(5-2)6-3;/h7H,4-6H2,1-3H3;/q-1;+1
			|PubChem = 23712863
	| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
			|UNII_Ref = {{fdacite|correct|FDA}}
	| StdInChIKey = WCJAYABJWDIZAJ-UHFFFAOYSA-N
			|UNII = Q1ML638JFD
	}}
			|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
	| Section2 = {{Chembox Properties
			|StdInChI = 1S/C6H16B.Li/c1-4-7(5-2)6-3;/h7H,4-6H2,1-3H3;/q-1;+1
	| Formula = Li(C<sub>2</sub>H<sub>5</sub>)<sub>3</sub>BH
			|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
	| MolarMass = 105.95 g/mol
			|StdInChIKey = WCJAYABJWDIZAJ-UHFFFAOYSA-N
	| Appearance = Colorless to yellow liquid
			|SMILES = .CC(CC)CC
	| Density = 0.890 g/cm<sup>3</sup>, liquid
			}}
	| Solubility = reactive
			|Section2={{Chembox Properties
	| BoilingPt = 66 °C for THF
			|Formula = Li(C<sub>2</sub>H<sub>5</sub>)<sub>3</sub>BH
	}}
			|MolarMass = 105.95 g/mol
	| Section7 = {{Chembox Hazards
			|Appearance = Colorless to yellow liquid
	| ExternalMSDS = |
			|Density = 0.890 g/cm<sup>3</sup>, liquid
	| MainHazards = highly flammable<br />corrosive<br />Causes burns<br />Probable Carcinogen
			|Solubility = reactive
	| NFPA-H = 3
	| NFPA-R = 2		|BoilingPtC = 66
			|BoilingPt_notes = for THF
	| NFPA-F = 2
			}}
	| NFPA-O = W
			|Section3={{Chembox Hazards
	| FlashPt =
			|ExternalSDS =
	| RPhrases = 11-14/15-19-34
			|MainHazards = highly flammable<br />corrosive<br />Causes burns<br />Probable Carcinogen
	| SPhrases = 16-26-33-36/37/39-43-45
			|NFPA-H = 3
	}}
			|NFPA-R = 2
	| Section8 = {{Chembox Related
			|NFPA-F = 2
	| Function = ]
			|NFPA-S = W
	| OtherFunctn = ]<br />]<br />]
			|GHS_ref=<ref>{{cite web |title=Lithium triethylhydroborate |url=https://pubchem.ncbi.nlm.nih.gov/compound/23712863#section=Safety-and-Hazards |website=pubchem.ncbi.nlm.nih.gov |access-date=19 December 2021 |language=en}}</ref>
	}}
			|GHSPictograms = {{GHS02}}{{GHS05}}{{GHS07}}
			|GHSSignalWord = Danger
			|HPhrases = {{H-phrases|250|260|314|335}}
			|PPhrases = {{P-phrases|210|222|223|231+232|260|261|264|271|280|301+330+331|302+334|303+361+353|304+340|305+351+338|310|312|321|335+334|363|370+378|402+404|403+233|405|422|501}}
			}}
			|Section4={{Chembox Related
			|OtherFunction_label = ]
			|OtherFunction = ]<br/>]<br />]<br />]
			}}
	}}		}}
	'''Lithium triethylborohydride''' (]]]]), commonly abbreviated to '''LiTEBH''' or '''Superhydride''', is a powerful and selective ] used in ] and ]. LiTEBH is far more powerful than ] and more powerful than ] (LAH) in many cases. One of the main advantages of LiTEBH is that it is safer than LAH.		'''Lithium triethylborohydride''' is the ] with the formula ]]]. Commonly referred to as '''LiTEBH''' or '''Superhydride''', it is a powerful ] used in ] and ]. It is a colorless or white liquid but is typically marketed and used as a THF solution.<ref name=HCB>{{cite book|author1=Zaidlewicz, M.|author2=Brown, H.C.|author-link2=Herbert C. Brown|chapter=Lithium Triethylborohydride|title=Encyclopedia of Reagents for Organic Synthesis|year=2001|publisher=John Wiley & Sons|doi=10.1002/047084289X.rl148|isbn=0471936235|url=https://doi.org/10.1002/047084289X.rl148.pub2|access-date=2022-02-18}}</ref> The related reducing agent ] is commercially available as ] solutions.
			LiBHEt<sub>3</sub> is a stronger reducing agent than ] and ].
	LiTEBH rapidly reduces:
	# ], ], acid chlorides and ] to ]
	# ] to diols
	# Acid anhydrides to alcohols
	# α,β-enones by 1,4-addition to give lithium ]
	# ] to ]
	# Tertiary ]s to an alcohol
	==History==
	Compounds of lithium hydride and sodium hydride with trialkylboranes such as LiTEBH were first discovered in the course of War Research in the period of 1942-45 at the University of Chicago by Professor H.C. Brown and Professor H.I. Schlesinger.<ref>Krishnamurthy, S. ''Aldrichim. Acta.'' '''1974,''' ''7,'' 55.</ref>
	==Preparation==		==Preparation==
	LiTEBH is most commonly produced by the reaction between ] (LiH) and ] (Et<sub>3</sub>B) in ] (THF)		LiBHEt<sub>3</sub> is prepared by the reaction of ] (LiH) and ] (Et<sub>3</sub>B) in ] (THF):
	:LiH + Et<sub>3</sub>B → LiEt<sub>3</sub>BH		:LiH + Et<sub>3</sub>B → LiEt<sub>3</sub>BH
			The resulting THF complex is stable indefinitely in the absence of moisture and air.
	which gives a very high yield of approximately 99%. The subsequent solution is collected by ] of any excess LiH to give a crystal clear solution. LiTEBH in THF has appeared to be stable indefinitely under an inert atmosphere.
			==Reactions==
	==Structure and chemical properties==
			Alkyl halides are reduced to the alkanes by LiBHEt<sub>3</sub>.<ref>{{cite journal|title=Lithium Triethylborohydride|author1=Marek Zaidlewicz|author2=Herbert C. Brown|journal=Encyclopedia of Reagents for Organic Synthesis|year=2001|doi=10.1002/047084289X.rl148|isbn=0471936235}}</ref><ref>{{cite journal|author1=Brown, H. C.|author2=Kim, S. C.|author3=Krishnamurthy, S.|title=Selective reductions. 27. Reaction of alkyl halides with representative complex metal hydrides and metal hydrides. Comparison of various hydride reducing agents|journal=J. Org. Chem.|date=1980-02-01|volume=45|issue=5|pages=849–856|doi=10.1021/jo01293a018|url=https://pubs.acs.org/doi/10.1021/jo01293a018|access-date=2022-02-18}}</ref><ref name=HCB/>
	The structure of LiTEBH causes the compound to be a very strong hydride source. Hydrogen is more electronegative than boron which causes the B-H bond to be strongly polarized with boron having a partial positive charge and hydrogen having a partial negative charge. The ethyl groups on the boron also aids to this abnormal polarizability by removing additional electron density from the boron making it even more electropositive. This polarization of the B-Et and B-H bonds causes the hydrogen to be in the (-I) oxidation state instead of its usual (+I) oxidation state which leads to its high reactivity with atoms that can accept electrons to allow the hydrogen to go to its (+I) oxidation state.
	==Uses==
	] and ] rapidly utilizes 1 equivalent of LiTEBH to form the alcohol shown respectively in (1) and (2).
	:]
	LiTEBH can be used to form the alcohol even when these compounds possess sterically hindered substituents as shown with 2,2,4,4-tetramethyl-3-pentanone in (3).
	:]
	] and ] rapidly take up 2 equivalents of LiTEBH, undergoing reduction to the alcohol and diol groups respectively. The example shown below involves the reduction of γ-butyrolactone to 1,4-butanediol which formed in a 94% yield in (4).<ref>Brown, H.C.; Kim, S.C.; Krishnamurthy, S. ''J. Org. Chem.'' '''1980,''' ''45,'' 1-12.</ref>
	:]
	The opening of the ] ring with LiTEBH proceeds with exceptional regio- and stereo- selectivity, yielding only the ] alcohol.<sup></sup> The example shown below is of 1,2-epoxybutane being reduced to give 1-methylcyclohexanol in (5).
			LiBHEt<sub>3</sub> reduces a wide range of functional groups, but so do many other hydride reagents. Instead, LiBHEt<sub>3</sub> is reserved for difficult substrates, such as sterically hindered carbonyls, as illustrated by reduction of 2,2,4,4-tetramethyl-3-pentanone. Otherwise, it reduces acid anhydrides to alcohols and the carboxylic acid, not to the ]. Similarly ]s reduce to diols. α,β-Enones undergo 1,4-addition to give lithium ]s. ]s reduce to ]s (via thiolates). LiBHEt<sub>3</sub> deprotonates carboxylic acids, but does not reduce the resulting lithium carboxylates. For similar reasons, ]s undergo ring-opening upon treatment with LiBHEt<sub>3</sub> to give the alcohol. With unsymmetrical epoxides, the reaction can proceed with high regio- and stereo- selectivity, favoring attack at the least hindered position:
	:]		:]
	The ] and ] will not be reduced by LiTEBH. LiTEBH can be used in the reductive cleavage of ] and ]s.<ref>Baer, H.H.; Mekarska-Falicki, M. ''Can. J. Chem.'' '''1985,''' ''63,'' 3043.</ref> LiTEBH can selectively deprotect tertiary N-acyl groups without affecting secondary amide functionality.<ref>Tanaka, H.; Ogasawara, K. ''Tetrahedron Lett.'' '''2002,''' ''43,'' 4417.</ref>		]s and ]s are not reduced by LiBHEt<sub>3</sub>. It can be used in the reductive cleavage of ] and ]s.<ref>{{cite journal|author1=Baer, H.H.|author2=Mekarska-Falicki, M.|title=Stereochemical dependence of the mechanism of deoxygenation, with lithium triethylborohydride, in 4,6-O-benzylidenehexopyranoside p-toluenesulfonates|journal=Canadian Journal of Chemistry|date=November 1985|volume=63|issue=11|page=3043|doi=10.1139/v85-505|url=https://doi.org/10.1139/v85-505|access-date=2022-02-18|doi-access=free}}</ref> LiBHEt<sub>3</sub> can selectively deprotect tertiary N-acyl groups without affecting secondary amide functionality.<ref>{{cite journal|author1=Tanaka, H.|author2=Ogasawara, K.|title=Utilization oh lithium triethylborohydride as a selective N-acyl deprotecting agent|journal=Tetrahedron Lett.|date=2002-06-17|volume=43|issue=25|page=4417|doi=10.1016/S0040-4039(02)00844-4|url=https://doi.org/10.1016/S0040-4039(02)00844-4|access-date=2022-02-18}}</ref> It has also been shown to reduce aromatic esters to the corresponding alcohols as shown in eq 6 and 7.
	LiTEBH has also shown high reactivity toward ester groups by the selective reduction of the ester group of aromatic carboxylic acids to alcohols as shown in (6) and (7).<sup></sup>
	:]		:]
	LiTEBH can also effectively reduce ] and ] to ] and tetrahydroisoquinolines respectively.<ref>Blough, B.E.; Carroll, F.I. ''Tetrahedron Lett.'' '''1993,''' ''34,'' 7239.</ref>		LiBHEt<sub>3</sub> also reduces ] and ] to ] and tetrahydroisoquinolines respectively.<ref>{{cite journal|author1=Blough, B.E.|author2=Carroll, F.I.|title=Reduction of isoquinoline and pyridine-containing heterocycles with lithium triethylborohydride (Super-Hydride®)|journal=Tetrahedron Lett.|date=1993-11-05|volume=34|issue=45|page=7239|doi=10.1016/S0040-4039(00)79297-5|url=https://www.sciencedirect.com/science/article/abs/pii/S0040403900792975|access-date=2022-02-18}}</ref>
	<br />The reduction of β-hydroxysulfinyl imines with catecholborane and LiTEBH produces ''anti-''1,3-amino alcohols shown in (8).<ref>Kochi, T; Tang, T.P.; Ellman, J.A. ''J. Am. Chem. Soc.'' '''2002,''' ''124,'' 6518.</ref>		<br />The reduction of β-hydroxysulfinyl imines with catecholborane and LiBHEt<sub>3</sub> produces ''anti-''1,3-amino alcohols shown in (8).<ref>{{cite journal|author1=Kochi, T.|author2=Tang, T.P.|author3=Ellman, J.A.|title=Asymmetric Synthesis of syn- and anti-1,3-Amino Alcohols|journal=J. Am. Chem. Soc.|date=2002-05-14|volume=124|issue=23|pages=6518–6519|doi=10.1021/ja026292g|pmid=12047156|url=https://doi.org/10.1021/ja026292g|access-date=2022-02-18}}</ref>
	:]		:]
	==Precautions==		==Precautions==
	LiTEBH reacts violently and exothermically with water, alcohols, or acids releasing flammable hydrogen gas which can ignite explosively and the ] ] vapor can ignite spontaneously. It can cause severe eye, skin, and respiratory tract burns.		LiBHEt<sub>3</sub> reacts exothermically, potentially violently, with water, alcohols, and acids, releasing hydrogen and the ] ].<ref name=HCB/>
	==References==		==References==
	<references/>		<references/>
			{{Lithium compounds}}
	==External links==
	*
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