Aldehydes and Ketones - Organic Chemistry II - Lecture Slides, Slides of Organic Chemistry

Download Aldehydes and Ketones - Organic Chemistry II - Lecture Slides and more Slides Organic Chemistry in PDF only on Docsity! Aldehydes and Ketones docsity.com Before you can learn about aldehydes and ketones, you must first know something about the nomenclature of carboxylic acids since many of the names of aldehydes and ketones are derived from the names of the corresponding carboxylic acids. docsity.com 5 4 3 2 1 C—C—C—C—C=O δ γ β α used in common names CH3CH2CH2CHCOOH Br CH3CHCH2COOH CH3  bromovaleric acid  -methylbutyric acid isovaleric acid docsity.com COOH COOH COOH COOH CH3 CH3 CH3 benzoic acid o-toluic acid m-toluic acid p-toluic acid Special names! docsity.com ALDEHYDES AND KETONES ―carbonyl‖ functional group: Aldehydes Ketones H C H O R C H O R C R' O R can be Ar C O docsity.com Aldehydes, IUPAC nomenclature: Parent chain = longest continuous carbon chain containing the carbonyl group; alkane, drop –e, add –al. (note: no locant, -CH=O is carbon #1.) CH3 CH3CH2CH2CH=O CH3CHCH=O butanal 2-methylpropanal H2C=O CH3CH=O methanal ethanal docsity.com Ketones, common names: Special name: acetone ―alkyl alkyl ketone‖ or ―dialkyl ketone‖ H3C C CH3 O CH3CH2CCH3 O CH3CH2CCH2CH3 O ethyl methyl ketone diethyl ketone CH3CCH2CH2CH3 O methyl n-propyl ketone docsity.com (o)phenones: Derived from common name of carboxylic acid, drop –ic acid, add –(o)phenone. CR O C O H3C C O benzophenone acetophenone docsity.com Spectroscopy: IR: C=O stretch, strong ~1700 cm-1 RCHO 1725 ArCHO 1700 R2CO 1710 ArCOR 1690 C—H stretch for aldehydes 2720 nmr: -CHO 9-10 ppm docsity.com LoD TRANSMITTANCE 4! HIT-NO=1153 [SCORE= ( 1] S0BS-NO=722 [IR-NIDA-05227 + LIQUID FILM ACETOPHENONE acetophenone Cate 5D 4 C=0— stretch 00 T 3000 T T T 2000 i500 L000 HAVENUMBER! if 3604 qage 3067 4ad63 4040 ad29 4006 a4 ai Te q2 qe 2987 2025 2687 1686 1646 1599 1684 PT 70 a4 6B 21 1646 1402 1450 1430 1360 1415 1303 al 1267 5 966 ST al llfi GB g28 T2 26 1160 74 761 15 be iloa 78 Tal 79 C—CH3 13 lo7a 62 Bal 14 | Ae 1o25 50 Bla Bi 3 loo) 74 bas 17 Qo docsity.com LoD TRANSMITTANCE 4! HIT-NO=4229 [SCORE= i 1 [S0BS-NO=10637 [IR-NIDA-0409% + LIQUID FILM VALERALDEHYOE valeraldehyde Cato +— C=O stretch 00 T 3000 T 2000 T T i500 L000 HAVENUMBER! if 3436 2960 24955 2876 2719 Je? L467 14l2 1390 i580 12B3 il4g 111g 1108 45 4B 5B al a7 35 gal gee 436 148 Tal 134 ays 43 da AG 7 17 al Bao al H»=C—(CH,},—C—0 H docsity.com Aldehydes, syntheses: 1. Oxidation of 1o alcohols 2. Oxidation of methylaromatics 3. Reduction of acid chlorides Ketones, syntheses: 1. Oxidation of 2o alcohols 2. Friedel-Crafts acylation 3. Coupling of R2CuLi with acid chloride docsity.com Aldehydes synthesis 1) oxidation of primary alcohols: RCH2-OH + K2Cr2O7, special conditions  RCH=O RCH2-OH + C5H5NHCrO3Cl  RCH=O (pyridinium chlorochromate) [With other oxidizing agents, primary alcohols  RCOOH] docsity.com CH3CH2CH2CH2CH2OH + K2Cr2O7 CH3CH2CH2CH2CO2H 1-pentanol pentanoic acid K2Cr2O7, special conditions! CH3CH2CH2CH2CH=O pentanal valeraldehyde CH2OH C5H5NHCrO3Cl pyridinium chlorochromate CH=O benzaldehydebenzyl alcohol CH3CH2CH2CH2CH2OH 1-pentanol docsity.com Aldehyde synthesis: 3) reduction of acid chloride LiAlH(O-t-Bu)3 lithium aluminum hydride tri-tert-butoxide O Cl isovaleryl chloride O H isovaleraldehyde R C O Cl LiAlH(O-t-Bu)3 R C O H docsity.com C O Cl LiAlH(O-t-Bu)3 C O H LiAlH(O-t-Bu)3 benzoyl chloride benzaldehyde CH3CHCH2C O Cl CH3 CH3CHCH2C O H CH3 isovaleryl chloride isovaleraldehyde docsity.com Ketone synthesis: 1) oxidation of secondary alcohols NaOCl cyclohexanol cyclohexanone isopropyl alcohol acetone K2Cr2O7 H OH O H3C C CH3 O CH3CHCH3 OH docsity.com Mechanism for Friedel-Crafts acylation EAS R C Cl O + AlCl3 RC=O + AlCl4 + RC=O RDS H CR O H CR O + AlCl4 C R O + HCl + AlCl3 docsity.com Ketone synthesis: 3) coupling of RCOCl and R2CuLi RCOCl + R'2CuLi R C O R' Cl O + (CH3CH2)2CuLi O Isobutyryl chloride 2-Methyl-3-pentanone lithium diethylcuprate docsity.com CuLi 2 + CHCH2CH2CH3 O Cl CCH2CH2CH3 O butyrophenone CH3CH2CH2C O Cl + CH3CH CH3 2 CuLi CH3CH2CH2CCHCH3 O CH3 2-methyl-3-hexanone docsity.com ketone 2o alcohol acid chloride + ArH acid chloride + R2CuLi NaOCl, etc. AlCl3 docsity.com 1. outline three different syntheses for benzaldehyde 2. outline three different syntheses for benzophenone 3. outline a different synthesis for each of the following compounds: cyclohexanone, 4-bromobenzaldehyde, 2-pentanone, valeraldehyde, acetophenone, isobutyraldehyde, docsity.com CH2OH K2Cr2O7 special conditions CH3 CrO3 (CH3CO)2O CH(OOCCH3)2 H2O C O Cl LiAlH(O-t-Bu)3 CH=O benzaldehyde Synthesize benzaldehyde three different ways. docsity.com O CH3CH2CH2CCH3 O CH3C O OH H K2Cr2O7 CH3 C Cl O + AlCl3 (CH3CH2CH2)CuLi + CH3 C Cl O docsity.com Br CHO CH3CH2CH2CH2CHO CH3CHCHO CH3 Br CH3 CH3CH2CH2CH2CH2-OH K2Cr2O7 special conditions CrO3 (CH3CO)2O H2O CH3CHC CH3 O Cl LiAlH(O-t-bu)3 The methods could be reversed for the last two syntheses. docsity.com