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Revision as of 09:43, 9 March 2011 editColmere (talk | contribs)44 editsmNo edit summary← Previous edit Latest revision as of 08:53, 23 June 2024 edit undoChristian75 (talk | contribs)Extended confirmed users, New page reviewers, Pending changes reviewers, Rollbackers114,301 edits Removing Category:Name reactions Category:Organic reduction reactions 
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{{chembox {{Chembox
| Verifiedfields = changed
⚫ | verifiedrevid = 399499776
| Watchedfields = changed
⚫ | Reference=<ref> and at ]</ref>
⚫ | verifiedrevid = 417932141
⚫ | Reference = <ref> and at ]</ref>
| ImageFile = Alpine-borane.svg | ImageFile = Alpine-borane.svg
| ImageAlt = Skeletal formula of alpine borane
| ImageFile1 = Alpine-borane-3D-balls.png
| ImageAlt1 = Ball-and-stick model of the alpine borane molecule
| IUPACName = 9-(2,6,6-Trimethylbicyclohept-3-yl)-9-bora-bicyclononane | IUPACName = 9-(2,6,6-Trimethylbicyclohept-3-yl)-9-bora-bicyclononane
| OtherNames = Alpine-Borane; ''B''-Isopinocampheyl-9-borabicyclononane; ''B''-3-Pinanyl-9-borabicyclononane | OtherNames = Alpine-Borane; ''B''-Isopinocampheyl-9-borabicyclononane; ''B''-3-Pinanyl-9-borabicyclononane
| Section1 = {{Chembox Identifiers |Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 17206399 | ChemSpiderID = 17206399
| PubChem = 9921373
| PubChem_Comment = R
| PubChem1 = 10890567
| PubChem1_Comment = S
| InChIKey = VCDGSBJCRYTLNU-AZWGFFAPBY | InChIKey = VCDGSBJCRYTLNU-AZWGFFAPBY
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI_Ref = {{stdinchicite|correct|chemspider}}
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = VCDGSBJCRYTLNU-AZWGFFAPSA-N | StdInChIKey = VCDGSBJCRYTLNU-AZWGFFAPSA-N
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 73624-47-2 | CASNo = 73624-47-2
| CASNo_Comment = (R isomer) | CASNo_Comment = (R isomer)
| CASNo1_Ref = {{cascite|correct|??}}
| CASNo1 = 42371-63-1 | CASNo1 = 42371-63-1
| CASNo1_Comment = (S isomer) | CASNo1_Comment = (S isomer)
| SMILES = CC4(C)1C4(C)(C1)B3C2CCCC3CCC2 | SMILES = CC4(C)1C4(C)(C1)B3C2CCCC3CCC2
| InChI = 1/C18H31B/c1-12-16-10-13(18(16,2)3)11-17(12)19-14-6-4-7-15(19)9-5-8-14/h12-17H,4-11H2,1-3H3/t12-,13-,14?,15?,16+,17-/m1/s1 | InChI = 1/C18H31B/c1-12-16-10-13(18(16,2)3)11-17(12)19-14-6-4-7-15(19)9-5-8-14/h12-17H,4-11H2,1-3H3/t12-,13-,14?,15?,16+,17-/m1/s1
}} }}
| Section2 = {{Chembox Properties |Section2={{Chembox Properties
| C=18|H=31|B=1 | C=18 | H=31 | B=1
| Appearance = Colorless liquid | Appearance = Colorless liquid
| Density=0.947 g/mL | Density = 0.947 g/mL
| MeltingPt= | MeltingPt =
| MeltingPt= | BoilingPt= >
| BoilingPtC = 55
| BoilingPt=>55 °C
}} }}
| Section7 = {{Chembox Hazards |Section7={{Chembox Hazards
| EUClass = {{Hazchem F}} | GHSPictograms = {{GHS02}}
| GHSSignalWord = Danger
| RPhrases = {{R17}}
| HPhrases = {{H-phrases|250}}
| SPhrases = {{S6}} {{S16}} {{S24}} {{S36/37/39}}
| PPhrases = {{P-phrases|210|222|280|302+334|370+378|422}}
}} }}
| Section8 = {{Chembox Related |Section8={{Chembox Related
| OtherAnions = | OtherAnions =
| OtherCations = | OtherCations =
}} }}
}} }}


'''Alpine borane''' is the commercial name for an ] that is used in ]. This ] is generated by treating ] with ] to give a sterically crowded trialkylborane. The resulting ] species can ]ly reduce ketones, aldehydes, even deutero aldehydes in what is known as the ], or simply the '''Midland Reduction''':<ref>M. Mark Midland "B-3-Pinanyl-9-borabicyclononane" in Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley, New York.{{DOI|10.1002/047084289X.rp173}}. Article Online Posting Date: April 15, 2001</ref> '''Alpine borane''' is the commercial name for an ] that is used in ]. It is a colorless liquid, although it is usually encountered as a solution. A range of alkyl-substituted borane are specialty reagents in organic synthesis. Two such reagents that are closely related to Alpine borane are ] and ].

⚫ :C<sub>8</sub>H<sub>12</sub>B-pinanyl + RCDO → C<sub>8</sub>H<sub>12</sub>BOCHDR + (+)-''d''-pinene
==Preparation and reactions==
:]
This ] is generated by treating ] with ].<ref name=CR>{{cite journal | title = Asymmetric reductions with organoborane reagents | author = M. M. Midland | journal = Chemical Reviews | year = 1989 | volume = 89 | issue = 7 | pages = 1553–1561 | doi = 10.1021/cr00097a010}}</ref>

This sterically crowded ] trialkylborane can ]ly reduce aldehydes in what is known as the '''Midland Alpine borane reduction''', or simply the Midland reduction.<ref>M. Mark Midland "B-3-Pinanyl-9-borabicyclononane" in Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley, New York.{{doi|10.1002/047084289X.rp173}}. Article Online Posting Date: April 15, 2001</ref>
⚫ :C<sub>8</sub>H<sub>12</sub>B-pinanyl + RCDO → C<sub>8</sub>H<sub>12</sub>BOCHDR + (+)-''d''-pinene


] of the resulting borinic ester affords the alcohol: ] of the resulting borinic ester affords the alcohol:
:C<sub>8</sub>H<sub>12</sub>BOCHDR + H<sub>2</sub>O → C<sub>8</sub>H<sub>12</sub>BOH + HOCHDR :C<sub>8</sub>H<sub>12</sub>BOCHDR + H<sub>2</sub>O → C<sub>8</sub>H<sub>12</sub>BOH + HOCHDR


It is also effective for the stereoselective reduction of certain acetylenic ketones.<ref>{{OrgSynth | author = M. Mark Midland and Richard S. Graham | title =Asymmetric Reduction of α,β-Acetylenic Ketones with ''B''-3-Pinanyl-9-Borabicyclononane: (R)-(+)-1-Octyln-3-ol | collvol = 7 | collvolpages = 402 | prep = CV7P0402}}</ref> It is also effective for the stereoselective reduction of certain acetylenic ketones.<ref>{{cite journal |year=1985| first1 = M. Mark|last1=Midland|first2= Richard S.|last2=Graham | title =Asymmetric Reduction of α,β-Acetylenic Ketones with ''B''-3-Pinanyl-9-Borabicyclononane: (R)-(+)-1-Octyln-3-ol | volume = 63 | page = 57 | doi = 10.15227/orgsyn.063.0057|journal=Organic Syntheses}}</ref> The reaction is proposed to involve formation of an adduct by coordination of the carbonyl oxygen to boron. Intramolecular hydride transfer from the pinane substituent to the carbonyl carbon ensues. Many substrates for the Midland reduction have a low steric group such as an alkyne<ref>''Intramolecular Arene-Alkyne Photocycloaddition'' M. C. Pirrung ]; '''1987'''; 52(8); pp 1635 - 1637; {{doi|10.1021/jo00384a057}}</ref> or a nitrile<ref> {{cite journal|doi=10.1021/jo00217a053 |title=Efficient Asymmetric Reduction of Acyl Cyanides with B-3-Pinanyl 9-BBN (Alpine-Borane) |date=1985 |last1=Midland |first1=M. Mark |last2=Lee |first2=Penny E. |journal=The Journal of Organic Chemistry |volume=50 |issue=17 |pages=3237–3239 }}</ref> so as to increase selectivity. Stereochemical control comes from coordination of the carbonyl bulky borane, followed by hydride transfer opposite the largest group.<ref name=CR/><ref name="Li">
{{cite book
| author = Li, J. J.
| title = Name Reactions, A Collection of Detailed Mechanisms and Synthetic Applications
| url = https://archive.org/details/namereactions00jjli
| url-access = limited
| publisher = Springer
| year = 2009|edition=4th
| location = New York, New York
| pages = –360
| isbn = 978-3-642-01052-1 }}</ref>
]


==Related reagents== ==See also==
{{Portal|Chemistry}}
A range of alkyl-substituted derivatives of borane and diborane are specialty reagents in organic synthesis. Two such reagents that are closely related to Alpine borane are ] and ].
* ]
* ]


== References == == References ==
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] ]
] ]

]