HC入OH<F,C入DH pKa 15.4 pK2=15.9 pK=12.4 14.6 12.4 alcohol pKa CHOH 15.1 HC人OH 15.9 17.1 CHa 19.2 H.C
Sec 2 Preparation of alcohols(REV Functional group transformation: -Functional groups such as alkyl halides,carboxylic acids,esters,alkenes,aldehydes,ketones,and ethers can be transformed into alcohols. C-C bond formation Alcohols can be formed from epoxides,aldehydes, ketones,esters,and acid chlorides as a consequence of C-C bond formation with Grignard or organolithium reagents Reduction of Carbonyl -Reduction of aldehyde yields 1 alcohol. Reduction of ketone yields 2 alcohol. -Reagents:Sodium borohydride,NaBH4.Lithium aluminum hydride,LiAlH4:Raney nickel
Sec 2 Preparation of alcohols(REV) ❖Functional group transformation: ◼ Functional groups such as alkyl halides, carboxylic acids, esters, alkenes, aldehydes, ketones, and ethers can be transformed into alcohols. ❖C-C bond formation ◼ Alcohols can be formed from epoxides, aldehydes, ketones, esters, and acid chlorides as a consequence of C-C bond formation with Grignard or organolithium reagents ❖Reduction of Carbonyl ◼ Reduction of aldehyde yields 1ºalcohol. ◼ Reduction of ketone yields 2ºalcohol. ◼ Reagents:Sodium borohydride, NaBH4；Lithium aluminum hydride, LiAlH4；Raney nickel
Synthesis (Review) Nucleophilic substitution of OH-on alkyl halide CH.(CH H H(CH2)5CH3 NaOH HO CH3 CH3 Hydration of alkenes -water in acid solution (not very effective) -oxymercuration -demercuration hydroboration -oxidation
Synthesis (Review) ❖Nucleophilic substitution of OH- on alkyl halide ❖Hydration of alkenes ◼water in acid solution (not very effective) ◼oxymercuration - demercuration ◼hydroboration - oxidation NaOH C H CH3 HO (CH2 )5CH3 C H CH3 Br CH3 (CH2 )5
Glycols (Review) Syn hydroxylation of alkenes sosmium tetroxide,hydrogen peroxide -cold,dilute,basic potassium permanganate Anti hydroxylation of alkenes -peroxyacids,hydrolysis
Glycols (Review) ❖Syn hydroxylation of alkenes ◼osmium tetroxide, hydrogen peroxide ◼cold, dilute, basic potassium permanganate ❖Anti hydroxylation of alkenes ◼peroxyacids, hydrolysis
1.C-C bond formation -Alcohols can be formed from epoxides, aldehydes,ketones,esters,and acid chlorides as a consequence of C-C bond formation with Grignard or organolithium reagents OH o= -OCH2CH3 2CH3MgBr H3O* -CH3 CH3 ether
1. C-C bond formation ◼Alcohols can be formed from epoxides, aldehydes, ketones, esters, and acid chlorides as a consequence of C-C bond formation with Grignard or organolithium reagents C O OCH2CH3 CH3MgBr ether C OH CH3 CH3 2 H3O +