您所在位置：网站首页 > 高等教育 > 大学课件哥伦比亚大学有机化学-第14章-有机金属化合物-用格里纳德试剂合成醇14.6

哥伦比亚大学有机化学-第14章-有机金属化合物-用格里纳德试剂合成醇14.6

28页

卖家[上传人]：d****y

文档编号：70632289

上传时间：2019-01-17

文档格式：PPT

文档大小：1.55MB

文档加载中……请稍候！
如果长时间未打开，您也可以点击刷新试试。

下载文档到电脑，查找使用更方便

0 金贝

/ 28 举报版权申诉马上下载

文本预览

下载提示

常见问题

1、14.6 Synthesis of Alcohols Using Grignard Reagents,Grignard reagents act as nucleophiles toward the carbonyl group,C,O, ,MgX,+,d,d+,H3O+,two-step sequence gives an alcohol as the isolated product,formaldehyde to give primary alcohols aldehydes to give secondary alcohols ketones to give tertiary alcohols esters to give tertiary alcohols,Grignard reagents react with:,formaldehyde to give primary alcohols,Grignard reagents react with:,Grignard reagents react with formaldehyde,C,O, ,d,d+,H3O+,produc

2、t is a primary alcohol,H,H,H,H,H,H,Example,diethyl ether,Cl,Mg,MgCl,CH2OMgCl,H3O+,CH2OH,(64-69%),formaldehyde to give primary alcohols aldehydes to give secondary alcohols,Grignard reagents react with:,Grignard reagents react with aldehydes,C,O, ,d,d+,H3O+,product is a secondary alcohol,H,R,H,R,H,R,Example,diethyl ether,Mg,H3O+,(84%),CH3(CH2)4CH2Br,CH3(CH2)4CH2MgBr,formaldehyde to give primary alcohols aldehydes to give secondary alcohols ketones to give tertiary alcohols,Grignard reagents react

3、 with:,Grignard reagents react with ketones,C,O, ,d,d+,H3O+,product is a tertiary alcohol,R“,R,R“,R,R“,R,Example,diethyl ether,Mg,H3O+,(62%),CH3Cl,CH3MgCl,O,Organolithium reagents react with aldehydes and ketones in the same way that Grignard reagents do.,14.7 Synthesis of Alcohols Using Organolithium Reagents,Example,(76%),+,1. diethyl ether 2. H3O+,14.8 Synthesis of Acetylenic Alcohols,Using Sodium Salts of Acetylenes,NaNH2,NH3,+,1. NH3,2. H3O+,(65-75%),+,CH3CH2MgBr,+,CH3CH3,diethyl ether,2. H

4、3O+,(82%),Using Acetylenic Grignard Reagents,14.9 Retrosynthetic Analysis,Retrosynthetic analysis is the process by which we plan a synthesis by reasoning backward from the desired product (the “target molecule“).,Retrosynthetic Analysis of Alcohols,Step 1 Locate the carbon that bears the hydroxyl group.,Retrosynthetic Analysis of Alcohols,Step 2 Disconnect one of the groups attached to this carbon.,Retrosynthetic Analysis of Alcohols,OH,Retrosynthetic Analysis of Alcohols,What remains is the co

5、mbination of Grignard reagent and carbonyl compound that can be used to prepare the alcohol.,Example,CH3MgX,There are two other possibilities. Can you see them?,Synthesis,1.,2. H3O+,CH3Br,Mg, diethyl ether,CH3MgBr,14.10 Preparation of Tertiary Alcohols From Esters and Grignard Reagents,Grignard reagents react with esters,C,O, ,MgX,+,d,d+,R,R,but species formed is unstable and dissociates under the reaction conditions to form a ketone,Grignard reagents react with esters,C,O, ,MgX,+,d,d+,R,R,CH3OMgX, ,this ketone then goes on to react with a second mole of the Grignard reagent to give a tertiary alcohol,Example,2 CH3MgBr,+,1. diethyl ether 2. H3O+,(CH3)2CHCCH3,OH,CH3,(73%),Two of the groups attached to the tertiary carbon come from the Grignard reagent,

《哥伦比亚大学有机化学-第14章-有机金属化合物-用格里纳德试剂合成醇14.6》由会员d****y分享，可在线阅读，更多相关《哥伦比亚大学有机化学-第14章-有机金属化合物-用格里纳德试剂合成醇14.6》请在金锄头文库上搜索。

点击阅读更多内容

TA的资源