tóm tắt phản ứng hóa hữu cơ part 1 hóa học hữu cơ là một ngành khoa học nghiên cứu về những cấu trúc, tính chất, thành phần, cách thức phản ứng, và cách tổng hợp của những hợp chất hữu cơ và vật liệu hữu cơ... cũng như nhiều vật chất khác nhau chứa nguyên tử carbon.12 Quá trình nghiên cứu cấu trúc hóa học của một hợp chất hữu cơ có thể ứng dụng nhiều thành tựu trong các lĩnh vực khác phải kể đến như phương pháp quang phổ, phương pháp vật lý và hóa học để định danh và xác định thành phần hóa học cũng như cấu tạo của hợp chất.3 Hóa hữu cơ nghiên cứu các đặc tính lý hóa của hợp chất, đánh giá mức độ phản ứng cũng như xác định tính chất của chúng ở trạng thái tinh khiết, trong dung dịch, hỗn hợp và các dạng khác. Các nghiên cứu về phản ứng hữu cơ có thể kể đến bao gồm việc chuẩn bị cho các phản ứng tổng hợp hữu cơ, nghiên cứu mức độ hoạt động của phản ứng, cũng như nghiên cứu các mô hình lý thuyết trên máy tính
Facilitator: Chris Lovero Organic Chemistry II Reactions Task Reaction Symmetrical ethers through dehydration of 1o alcohols R OH H2SO4 x2 140oC O CH3 Cleavage of ethers byvstrong acids Notes R *cannot be unsymetrical O R (you will get mixtures!) Br HBr *can also use HI, HCl, + H3C Br etc * vinyl or aryl not get cleaved (NO SN2 ON SP2) HBr Br O HO *basically forms Autoxidation R R O R O2 (xs) H R O slow R + R O O MCPBA CH3 Intramolecular Williamson Br H EXPLODE! CH3 *epoxide will form along O the more substituted CH3 alkene *SN2 like O NaOH OH peroxides which R R CH3 MCPBA O OH R *forms O- that attacks halogenated C OH NaOH H3C H3C O Cl Opening of Epoxides CH3 CH3 H3O+ O D H2O CH3 D OH 2)H3O+ *weak Nu are good *more substituted side attacked D OH 1)-OH O OH *activate the O first *SN2 like (least subs) so strong Nu and base CH3 D OH *Grignard reagent and acetylide anion can work tooo Facilitator: Chris Lovero Organic Chemistry II Reactions Task Reaction Free Radical Halogenation Expanded Notes *Low T: more stable TS CH3 NBS hv 0oC CH3 CH3 *High T: more stable Br compound CH3 NBS 60oC transition state CH3 CH3 CH3 CH3 CH3 CH3 Br Conjugated Systems *Low T: more stable TS *in this example we will examine the case of HBr *High T: more stable compound CH2 H2C *NOTE: If more than one H3O+ HBr conjugated system Br2 possibly exists, examine the transition states of HBr / 40oC HBr / 0oC H each one and the reactions with the more H stable transtion states! H2C Br Br transition state + Diels-Alder Reaction D = donating group + *1,2 or 1,4 adduct W = withdraw group D heat + *know endo rule D *Diene and Dienophile *Know Stereochem W W D D heat + W W *PRACTICE THIS!!! Facilitator: Chris Lovero Organic Chemistry II Reactions NOTE: FROM HERE, YOU HAVE TO KNOW YOUR META, ORTHO, AND PARA DIRECTORS Task Reaction Halogenation of Benzene Notes *X = Cl or Br X X2, FeX3 or (I2 / CuCl2) Nitration of Benzene NO2 HNO3 *H2SO4 acts as a catalyst H2SO4 heat Sulfonation (fuming sulfuric) SO 3H SO3 / H2SO4 *REVERSIBLE DUE TO ENTROPY heat SO 3H + H2SO + H2O *watch rearrangement! Friedel-Crafts Alkylation R RCl *no strong deactivators (no strong W grps) *no amino groups AlCl3 *watch for polyalkylation Friedel-Crafts Acetylation O O *no strong deactivators (no strong W grps) Cl R R *no amino groups AlCl3 O Gatterman-Koch Formation (forming benzaldehyde) Clemmensen Reduction CO / HCl *no strong deactivators (no strong W grps) H *no amino groups AlCl3 / CuCl *avoid using this O Zn(Hg) R HCl reactant in the presence R of alkenes, alkynes, alcohols and amines Facilitator: Chris Lovero Organic Chemistry II Reactions Task Reaction *Do not confuse with Reduction of Nitro group into Amino Group Zn, Sn, or Fe W = withdraw group X = leaving grp (halide) NH2 *need Strong W groups Nu = nucleophile X ortho and/or para to Nu Nu (2eq) W W Clemmenson Red HCl NO2 Nucleophilic Aromatic Substitution of Aryl Halides: Notes leaving group W W heat, pressure *Nu can be OH-, RO-, Addition / Elimination NH3 W *NOTE: If - OCH3 is the W Nu, only need eq X Nucleophilic Aromatic Substitution of Aryl Halides: Elimination / Addition OH *occurs when Strong W group is not O/P 1) NaOH (2eq) / 340oC / 2500 psi *formation of benzyne 2) H3O+ in mechanism X * Nu can be OH-, RO-, NH2 NaNH2 / NH2 + NH3 (l) NH2 *will get a mixture (like second example) CH3 CH3 CH3 Chlorination of Benzene *8 different stereochems Cl actually occur Cl Cl Cl2 / heat pressure *this particular molecule is the commercial Cl Cl compound Rid (lice killer) Cl Catalytic Hydrogenation - H2 / 1000 psi / 100oC Ru or Rh (Pt,Pd,Ni also) Birch Reduction W W *withdraw groups -> sp3 D Na or Li NH3(l) / ROH *donating groups -> D sp2 Facilitator: Chris Lovero Organic Chemistry II Reactions Task Reaction Side Chain Rxn: Oxidation Notes *Can use either reagent CO2H (CH2)n *Does not work for bulky KMnO4/H2O O groups OH-/100oC HO2 C CO2 H CO2 H Na2Cr2O7 / H2SO4 (no rxn) heat Halogenation of side chains *If aromatic ring is Cl CH2CH3 Cl2 / light activated, use NBS + Cl 54% 44% Br2 (or NBS) / light instead of Br2 *Pay attention to Temp (if it's low or high) *WILL EXPLAIN THIS Br BETTER IN CLASS Nucleophilic Subs of Benzylic Halides major! *SN1 CH2 Br CH3OH *SN1 or SN2 or E2? + Depends on conditions! heat *Resonance form that + does not disrupt the CH2 OCH3 aromaticity is more stable I NaI *SN2 Br acetone CH3CH2O- *E2 Na+ Rxns of phenols similar to alochols O NaOH - *2nd rxn is Fischer Estherification *3rd rxn is only one that OH RCO2H O O or RCOCl PBr3 R OH (no rxn) is different! Facilitator: Chris Lovero Organic Chemistry II Reactions Task Reaction Oxidation of Phenols to Quinones HO Notes *This reaction forms a Na2Cr2O7 OH O H2SO4 Formation of Salycilic Acid *Phenoxide anion can 1) NaOH OH OH O 2) CO2 3) H3O REVIEW: Oxidation of alcohols D-A dienophile! O 2o alcohols react with the weak OH electrophile because it + is so strongly activated *any [ox] can be used Na2CrO7 *KMnO4 and NO3 can H2SO4 / H2O OH be used but they are harsh O CrO3 / H2SO4 / H2O acetone / 0oC (Jones reagent) PCC CH2Cl2 H 1o alcohols PCC OH *Only use PCC because Jones reagent will O yield carboxyllic acid CH2Cl2 REVIEW: Cleavage of Alkenes by Ozonolysis H3C CH3 H O R H2O / H2SO4 R H R + CH3 O H 2) (CH3)2S CH3 REVIEW: Hydration of Alkynes H3C 1) O3 H CH3 *Really know the R CH3 HgSO4 HO 1) Sia2BH R 2) H2O2 / OH- H H mechanism now and how the enols O tautomerize R H H RCH2 either reagent O OH mixture of ketones Facilitator: Chris Lovero Organic Chemistry II Reactions Task Dithiane Synthesis of Aldehydes and Ketones Reaction Notes *Dithiane will be given O 1) BuLi S H S S 2) R - X H R S R HgCl2 H *BuLi = H3O+ H CH3(CH2)2CH2-Li *Halide must be methyl or 1o 1) BuLi 2) R1 - X S R Ketones from Carboxylic Acids O R Ketones from Nitriles S R O H3O+ R HgCl2 2) H3O Aldehydes from Acid Chlorides *2 eq because first is used to make salt + R R O 1) R1-MgX R C N O 1) R1 - Li (2eq) OH R R 2) H3O+ R *lithium aluminum tri(t-butoxy)hydride LiAlH(OtBu)3 O R O *Rosenmund Reduction Cl R H2 / Pd / BaSO4 / S H *Make sure you know Ketones from Acid Chlorides O R O (R1)2CuLi R Cl how to form Gilman R Reagent (refer to Corey- House in previous rxn sheet) Wittig Reaction: Ald and Ketones ONLY H *Know how to prep the H phosphorous ylide! H O (Ph)3 *trans is more stable P C because you want + H bulky groups to be furthest away from each other H H maj Facilitator: Chris Lovero Organic Chemistry II Reactions Task Aldehydes and Ketones: Formation of Cyanohydrins Reaction O R *Aldehydes or OH - unhindered ketones CN H R C CN HCN *will use this as a H reagent in the future OH O H3CH2C Notes NaCN H3CH2C C CN H+ H H *non AQ favors reactant Aldehydes and Ketones: Addition of 1o Amines O RNH2 C Wolf-Kishner Reaction *AQ favors product C N R H+ *avoid halogens and O NH2NH2 other good LGs KOH/DMSO (Use Clemmensen instead) Aldehydes and Ketones: Addition of 2o Amines O (H3C)2N (CH3)2NH H3O+ Acetal Formations "protected carbonyls" CH3 OEt CH3 2(CH3CH2OH) H+ O EtO *aldehyde protected *easier to just use OH OH O 1) OH + HO before ketone because CH OH /H it is more reactive 2) CH3MgBr H H 3) H3O+ O O O O - CH H O O H O O ...Facilitator: Chris Lovero Organic Chemistry II Reactions Task Reaction Free Radical Halogenation Expanded Notes *Low T: more stable... Dienophile *Know Stereochem W W D D heat + W W *PRACTICE THIS!!! Facilitator: Chris Lovero Organic Chemistry II Reactions NOTE: FROM HERE, YOU HAVE TO KNOW YOUR META, ORTHO, AND PARA DIRECTORS Task... in the presence R of alkenes, alkynes, alcohols and amines Facilitator: Chris Lovero Organic Chemistry II Reactions Task Reaction *Do not confuse with Reduction of Nitro group into Amino Group