Organic Mechanisms. Xiaoping Sun

6.21 Stereoselectivity of the S_N1 reactions.FIGURE 6.22 The S_N1 and S_N2 reactions of (R)‐2‐bromobutane performed in diff...FIGURE 6.23 The S_N1 (a) and S_N2 (b) hydrolysis of benzyl chloride.FIGURE 6.24 The S_N2 reaction of a Grignard reagent with ethylene oxide.FIGURE 6.25 (a) Regiospecific S_N2 reaction of phenylmagnesium bromide with a...FIGURE 6.26 The S_N2 reactions of alkyne anions with primary haloalkanes.FIGURE 6.27 The Gabriel synthesis.FIGURE 6.28 The S_N2 reaction of triphenylphosphine (Ph₃P) with a primary hal...FIGURE 6.29 Neighboring group‐assisted nucleophilic substitution reaction of...FIGURE 6.30 Neighboring group‐assisted hydrolysis of mustard gas.FIGURE 6.31 Mechanism and stereochemistry for neighboring group‐assisted nuc...FIGURE 6.32 Neighboring group assisted nucleophilic substitution of trans‐2‐...FIGURE 6.33 Mechanisms for the alcohol nucleophilic substitution reactions c...FIGURE 6.34 The S_N2 mechanism for alkylation of guanine in a DNA molecule by...FIGURE 6.35 The intrastrand crosslink between nitrogen bases of a DNA chain ...FIGURE 6.36 Cyclic structures of α‐ and β‐D‐glucose and α‐ and β‐glycoside. ...FIGURE 6.37 Mechanisms for (a) retaining β‐glucosidases; and (b) inverting β...FIGURE 6.38 Mechanism for hydrolysis of bacteria walls polysaccharide by lys...FIGURE 6.39 Biosynthesis of geraniol through S_N1 reactions.FIGURE 6.40 Biosynthesis of epinephrine from norepinephrine and S‐adenosylme...FIGURE 6.41 An enzyme‐catalyzed S_N2 reaction of an haloalkane.

      7 Chapter 7FIGURE 7.1 The E2 reaction mechanism.FIGURE 7.2 The E2 reaction of 2‐bromo‐2‐methylpentane induced by different b...FIGURE 7.3 Steric hindrance of t‐butoxide on the E2 reaction of 2‐bromo‐2‐me...FIGURE 7.4 Reactions of cis‐ and trans‐4‐(t‐butyl)cyclohexyl tosylate with tFIGURE 7.5 The E2 reactions of trans‐ and cis‐1‐bromo‐2‐methylcyclohexane in...FIGURE 7.6 The E2 reactions of 1‐bromo‐1‐methylcyclohexane induced by differ...FIGURE 7.7 Stereochemistry for the E2 reactions of different stereoisomers o...FIGURE 7.8 (a) Anti‐coplanar arrangement of the C_α─X and C_β─H bond...FIGURE 7.9 Correlations of frontier molecular orbitals for the E2 reaction o...FIGURE 7.10 Syn‐coplanar arrangement of the C_α─X and C_β─H bonds in...FIGURE 7.11 (a) Chair‐conformations of a halocyclohexane (X = Cl, Br, or I)....FIGURE 7.12 Basicity versus nucleophilicity for various species.FIGURE 7.13 E2 and S_N2 reactions for an epoxide.FIGURE 7.14 Competition between E2 and S_N2 reactions.FIGURE 7.15 Ethoxide (⁻OEt) induced E2 reactions versus S_N2 reactions ...FIGURE 7.16 The E1 reaction mechanism.FIGURE 7.17 The acid‐catalyzed dehydration of (a) 2‐methyl‐2‐butanol and (b)...FIGURE 7.18 Bell–Evans–Polanyi principle: dependence of activation energy on...FIGURE 7.19 Reaction profiles for E1 dehydrations of 2‐methyl‐2‐butanol and ...FIGURE 7.20 The acid‐catalyzed E1 dehydration of 1‐cyclohexylethanol.FIGURE 7.21 Reaction profiles for E1 reactions of haloalkanes.FIGURE 7.22 Mechanism for the E1 elimination of a tertiary butyl ether.FIGURE 7.23 Mechanism for the unimolecular syn‐elimination of an ester.FIGURE 7.24 Examples for unimolecular syn‐eliminations of esters: (a) ethyl ...FIGURE 7.25 Silyloxide elimination: (a) Base‐induced syn‐elimination and (b)...FIGURE 7.26 Mechanism for zinc‐induced anti‐eliminations of vicinal dihalide...FIGURE 7.27 Mechanism for reductive anti‐elimination of vicinal alkane dihal...FIGURE 7.28 Reductive elimination of a chlorinated ethylene by metallic zinc...FIGURE 7.29 (a) Molecular orbitals (MOs) in CHCl₃ which are formed by linear...FIGURE 7.30 Molecular orbital diagram for the base induced α‐elimination of ...FIGURE 7.31 Energy profile for a base‐initiated E1cb reaction.FIGURE 7.32 Elimination of NMe₃ from a quaternary amine, which possesses an ...FIGURE 7.33 The FAD‐facilitated E1cb‐like elimination: a biological eliminat...FIGURE 7.34 An enzyme‐catalyzed E1cb elimination involved in biosynthesis of...FIGURE 7.35 The E1 mechanism for biosynthesis of limonene from linalyl dipho...

      8 Chapter 8FIGURE 8.1 (a) Addition of a strong nucleophile to a ketone or aldehyde; (b)...FIGURE 8.2 Mechanism for the hydroxide base catalyzed hydrolysis of ester (e...FIGURE 8.3 Acid and base catalyzed hydration of ketone or aldehyde.FIGURE 8.4 Mechanism for oxygen exchange between acetone and water.FIGURE 8.5 Mechanism for acid catalyzed nucleophilic addition of methanol to...FIGURE 8.6 Acid catalyzed nucleophilic addition reactions of various alcohol...FIGURE 8.7 Acid catalyzed reaction of an ester‐aldehyde with methanol, follo...FIGURE 8.8 The intramolecular nucleophilic addition of 6‐hydroxyl‐2‐heptanon...FIGURE 8.9 Cyclic structures and mutarotation of D‐glucose: the intramolecul...FIGURE 8.10 Cyclic structures and mutarotation of D‐fructose: the intramolec...FIGURE 8.11 Formations of cyclic structures of five‐carbon and six‐carbon su...FIGURE 8.12 Mechanism for acid catalyzed nucleophilic addition of an amine t...FIGURE 8.13 Reactions of a ketone or aldehyde to various compounds containin...FIGURE 8.14 Mechanism for reaction of a secondary amine with a ketone (cyclo...FIGURE 8.15 The enzymatic mechanism for conversion of fructose‐1,6‐bisphosph...FIGURE 8.16 Mechanism for nucleophilic addition of borohydride to a ketone o...FIGURE 8.17 Mechanism for nucleophilic addition of aluminum hydride to a ket...FIGURE 8.18 Structures of NAD(P)⁺ and NAD(P)H (biological hydride donor).FIGURE 8.19 Mechanism for lactate dehydrogenase (LDH) catalyzed homolactic f...FIGURE 8.20 Structures of FAD and FADH₂ (biological hydride donor).FIGURE 8.21 Reaction of a carboxylic acid with thionyl chloride.FIGURE 8.22 (a) Fischer esterification and reaction mechanism; and (b) react...FIGURE 8.23 Formation of a lactone by the entropy‐driven intramolecular este...FIGURE 8.24 (a) Structure of p‐dodecylbenzenesulfonic acid (DBSA); and (b) t...FIGURE 8.25 The p‐dodecylbenzenesulfonic acid (DBSA) catalyzed esterificatio...FIGURE 8.26 Formation of a cyclic carboxylic anhydride (succinic anhydride) ...FIGURE 8.27 Nucleophilic addition of ⁿBuLi to a carboxylic acid.FIGURE 8.28 Nucleophilic acyl substitution reactions of an alcohol with an a...FIGURE 8.29 Mechanism for acid catalyzed esterification reaction of salicyli...FIGURE 8.30 Nucleophilic acyl substitution reactions of a primary amine with...FIGURE 8.31 Nucleophilic acyl substitution reaction of a primary amine with ...FIGURE 8.32 Mechanisms for acid and base catalyzed transesterification.FIGURE 8.33 Synthesis of biodiesel from corn oil.FIGURE 8.34 Mechanism for the formation of methyl ester of fatty acids (biod...FIGURE 8.35 The hydrolytic peptide bond cleavage in proteins catalyzed by se...FIGURE 8.36 The catalytic mechanism for trypsin (a serine protease).FIGURE 8.37 The reaction profile for the trypsin catalyzed hydrolytic cleava...FIGURE 8.38 Lipase catalyzed hydrolysis of triacylglycerol to fatty acids.FIGURE 8.39 Enzymatic mechanism for hydrolysis of triacylglycerol catalyzed ...FIGURE 8.40 Reductions of (a) acyl chlorides, carboxylic anhydrides, and est...FIGURE 8.41 Mechanism for reduction of an amide to an amine by lithium alumi...FIGURE 8.42 Mechanism for cyanide catalyzed nucleophilic addition of benzald...

      9 Chapter 9FIGURE 9.1 Molecular orbitals formed due to the hyperconjugation between the...FIGURE 9.2 Formation of the enolate from a carbonyl compound and its equilib...FIGURE 9.3 Crystal structure of lithium enolate of 2,2‐dimethyl‐2‐butanone....FIGURE 9.4 Regiochemistry for deprotonation of unsymmetrical ketones by LDA ...FIGURE 9.5 Occupied molecular orbitals for the three‐center, four‐electron b...FIGURE 9.6 Alkylation of carbonyl compounds via enolates and primary alkyl h...FIGURE 9.7 Alkylation of carbonyl compounds via enolates and primary alkyl d...FIGURE 9.8 Alkylation of (a) an aldehyde and (b) a ketone via N,N‐dimethylhy...FIGURE 9.9 Alkylation of a ketone via a secondary amine.FIGURE 9.10 The general mechanism for an aldol reaction of an aldehyde or ke...FIGURE 9.11 The crossed aldol condensation reactions between (a) benzaldehyd...FIGURE 9.12 Transition states and stereochemistry for the aldol reaction of ...FIGURE 9.13 The intramolecular aldol condensations to form cyclic α,β‐unsatu...FIGURE 9.14 The aldol reaction of benzaldehyde with acetic anhydride catalyz...FIGURE 9.15 The acid catalyzed aldol condensation of acetone via an enol.FIGURE 9.16 Mechanism for the (S)‐proline catalyzed enantiomerically specifi...FIGURE 9.17 Mechanism for the (S)‐proline catalyzed enantiomerically specifi...FIGURE 9.18 Mechanism for the (S)‐proline catalyzed diastereoselective aldol...FIGURE 9.19 Diastereoseletive aldol reactions of (a) (Z)‐ and (b) (E)‐enolat...FIGURE 9.20 (a) Nucleophilic 1,2‐ and 1,4‐additions to an α,β‐unsaturated ca...FIGURE 9.21 (a) Resonance structures and (b) the occupied molecular orbitals...FIGURE 9.22 Mechanism for the Robinson annulations.FIGURE 9.23 Darzens condensation: Reaction and mechanism.FIGURE 9.24 Mechanism for Claisen