Mechanism of reduction O|C OH H H20 H C一 A carbonyl An alkoxide ion An alcohol compound intermediate @2004 Thomson/Brooks Cole
Mechanism of Reduction
Alcohols from grignard reaction 8+Mgx 0 8-人 δ+ R"MgX R"H30 OH R R H(R RHR) RHR) RMg R" H2O+ OH R R0(R) RR R R
Alcohols from Grignard Reaction MgX O C d - d - d + d + R H(R') O R H(R') O - R'' R''MgX H3O + R H(R') OH R'' R O(R') O R R'' O - R'' R''MgX H3O + R R'' OH R
Formaldehyde reaction M CHoH +H-C-H、1N 2.H1O+ Cyclohexylmagnesium Formaldehyde Cyclohexylmethanol (65%) bromide (a1° alcohol) Aldehyde reaction CH. O CH, OH 1. Ether solvent CH3CHCH2CH+ 2.H2O →CH2CHCH2CH 3. Methylbutanal Phenylmagnesium 3-Methyl-1- phenyl-l-butanol (73%) bromide (a2° alcohol) Ketone reaction OH 1. CH CHoMg Br, ether CHOCH3 H3 Cyclohexanone 1-Ethylcyclohexanol(89%) (a3° alcohol) ②2004 Thomson/ Brooks Cole
Reactions of esters and Grignard reagents Yields tertiary alcohols in which two of the substituents carbon come from the grignard reagent OH Ch Cho Ch COChoCH4tngmgd, ch chchch CcH,+CHCH OH Ethyl pentanoate CH3 2-Methyl-2-hexanol(85%) (a3° alcohol) @2004 Thomson /Brooks Cole
Reactions of Esters and Grignard Reagents • Yields tertiary alcohols in which two of the substituents carbon come from the Grignard reagent
Mechanism of the addition of a grignard reagent Grignard reagents act as nucleophilic carbon anions(carbanions, R)in add ing to a carbonyl group The intermediate alkoxide is then protonated to produce the alcohol 6 OH R HO C C 0+ R R A carbonyl An alkoxide ion An alcohol compound intermediate 22004 Thomson Brocks Cole
Mechanism of the Addition of a Grignard Reagent • Grignard reagents act as nucleophilic carbon anions (carbanions, : R- ) in adding to a carbonyl group • The intermediate alkoxide is then protonated to produce the alcohol