Ochem Exam 3Chapter 20: Carboxylic Acid Derivatives- Reactivity of Acyl Halides > Anhydrides > Esters > Amides- Reactions of Acyl Halideso Reduction (via LiAl(OtBu)3H) to aldehydeso Esterification (via R’OH) o Amidation (via R’NH2)o Alkylation (via R’2CuLi)- Reactions of Carboxylic Anhydrideso Esterification (via R’OH) o Amidation (via R’NH2)- Reactions of Esterso Hydrolysis Acid-Catalyzed- No negative charge Base-Promoted- No positive chargeo Transesterification Ester + R’OH & Acid/Baseo Ester to Amide Ester + R’’NH2 & Heato Ester w/ Grignard Ester + 2 R’’MgX to a tertiary alcoholo Reduction To primary alcohols (via LiAlH4) To aldehydes (via DIBALH)o α – Alkylation (via LDA & R’’X)- Reactions of Amideso Hoffman Rearrangement Amide + NaOH, X2, H2O to RNH2o Reduction To primary amines (via LiAlH4) To aldehydes (via DIBALH)- Reactions of Nitrileso Hydrolysis RCN + Acid/Base & H2O- 2 steps:1. Nitrile to Amide2. Amide to Carboxylic Acido Nitriles w/ Grignards RCN + R’M (M = Li or MgX) then H3O+ to form ketoneso Reduction To primary amines (via LiAlH4) To aldehydes (via DIBALH)Chapter 21: Amines & Their Derivatives- Primary Amine Synthesiso RX + KCN, then LiAlH4 RCH2NH2o RX + NaN3, then LiAlH4 RNH2o Gabriel Synthesis (via Hydrazine)- Reductive Aminationo w/ primary & secondary amineso (via NaBH3CN) Only reduces imines- Hoffman Eliminationo Only occurs with quaternary amineso Ag2O, H2O, heato Occurs at the anti-periplanar positiono E2 Mechanism – formation of a double bond- Mannich Reactiono Step 1: Imminium ion formationo Step 2: Tautomerizationo Step 3: Nu attacks Eo Occurs in the presence of acid- Nitrosation of Amineso R2NH + NaNO2 & HClo Can go further to become N2Chapter 22: Chemistry of Benzene Substituents- Benzylic Radicalso Stable due to resonanceo Bromination can occur at benzylic position- Benzylic Cationso MeO Facilitates SN1 rxns- Benzylic Anionso NO2- Reduction of Bno (via H2 & Pd) ROHo Good for protecting groups in synthesis- Preparation of Phenolso Addition-Elimination w/ Nu (OH) Occurs at ipso- position Requires EWG at ortho- and/or para- positiono Elimination-Addition via Benzyne Base & ortho-X, E+ at the end (aldehyde or water)o Arenediazonium Salts (via N2+) and then water/heato Palladium Catalysis – Buchwald – Hartwig Rxn KOH/RNH2 & Pd, R’3P- Kolbe-Schmitt Rxno Phenol + NaOH, CO2, & H2O adds a CO2-o In other words, adds a carboxylic acid to a phenol- Claisen/Cope Rearrangemento Driving force: carbonyl is more stable than estero Want to restore aromaticity at the end if possibleo Push arrows backwards for retro-synthesis- Formation of Benzoquinoneso Benzoquinones are electron-deficient More likely to go through further reactions- Sandmeyer Reactiono N2+ gets replaced w/ R R = Cl, Br, I, CN, OH- Diazo Couplingo N2+ connects the two Important Regents- H2, Pd OR Zn, HClo Reduces NO2 to
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