Chem 232 Lecture 12 - UIC Department of Chemistry - University of ...

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Oxidation StephydroborationB 2 H 6diglymeHBH 2 oxidationH 2 O 2NaOH (aq)HOHcarried out in the same reaction vessel(boranes are reactive)• boron is replaced bymore electronegativeatom (O); therefore:oxidation• oxidation usingperoxide (H 2 O 2 ) &hydroxide (OH – ); addedimmediately afterhydroboration• I will not ask you tolearn the mechanismfor this step; for thecurious, see textbookpage 250University of IllinoisUICat Chicago CHEM 232, Spring 2010Slide 10Lecture 12: February 1810
Hydroboration-Oxidation is Regioselective1. B 2 H 6 , diglyme2. H 2 O 2 , NaOHCH 3 1. H 3 B•S(CH 3 ) 22. H 2 O 2 , NaOH1. H 3 B•THF2. H 2 O 2 , NaOHOHOHCH 3OH• usually written as a twostepprocess• works with diborane (B 2 H 6 )or a borane complex withanother Lewis base• diglyme is a commonsolvent• affords alcohol products;similar to hydration (H2O/H3O + )University of IllinoisUICat Chicago CHEM 232, Spring 2010Slide 11Lecture 12: February 18Which carbon of the alkene becomes bonded to the -OH group? Do you see a pattern here?11
Page 1 and 2: CHEM 232Organic Chemistry IUniversi
Page 5 and 6: Boranes - Structure & ElectronicsHH
Page 8 and 9: Stoichiometry of Hydroboration6 xB
Page 12 and 13: Regioselectivity DeterminedDuring H
Page 14 and 15: Regioselectivity - 1st RationaleSte
Page 16 and 17: Self Test QuestionWhat is the produ
Page 18 and 19: Alkene-Halogen AdditionC C + X Yadd
Page 20 and 21: Halogenation is Stereospecific• a
Page 22 and 23: Stereospecific ReactionsStereospeci
Page 24 and 25: Halogen Addition DoesNot Involve Fr
Page 26 and 27: Anti Addition..-: Br:....Br..:..Br.
Page 28 and 29: Halogen Addition Modification:Aqueo
Page 32 and 33: Epoxides are Preparedvia Alkene Epo
Page 34 and 35: Alkenes are Cleaved via Ozonolysiso
Page 38 and 39: Synthetic RouteHow could you prepar
Page 40 and 41: Self Test QuestionDevise a retrosyn
Page 42 and 43: Self Test QuestionWhich starting ma
Page 44: Quiz & Exam AveragesQuiz 1 = 61%Qui

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