- KCN K+ R KOH + H2O
... Remember, RBr ⇒ ROH; and we have seen that RCHO or R2CO ⇒ R”CH2OH or R”2CHOH (oxidation of aldehydes and ketones) Which starting materials would you use to prepare PhCH=C(CH3)2? PhCHO and (CH3)2CHBr versus PhCH2Br and (CH3)2CO? How would you prepare PhCH2Br from PhCOOMe? How would you prepare PhCHO ...
... Remember, RBr ⇒ ROH; and we have seen that RCHO or R2CO ⇒ R”CH2OH or R”2CHOH (oxidation of aldehydes and ketones) Which starting materials would you use to prepare PhCH=C(CH3)2? PhCHO and (CH3)2CHBr versus PhCH2Br and (CH3)2CO? How would you prepare PhCH2Br from PhCOOMe? How would you prepare PhCHO ...
Exam 2 review sheet
... five nucleophilic reactions of aldehyde/ketone: relative reactivity of aldehydes versus ketones; reactions 14 are reversible; (1) hydrate formation; acid or base catalysis; (2) cyanohydrin formation, base catalysis only; (3) hemiacetal formation, acid or base catalysis; acetal formation, only acid c ...
... five nucleophilic reactions of aldehyde/ketone: relative reactivity of aldehydes versus ketones; reactions 14 are reversible; (1) hydrate formation; acid or base catalysis; (2) cyanohydrin formation, base catalysis only; (3) hemiacetal formation, acid or base catalysis; acetal formation, only acid c ...
Document
... or ketone and a phosphorus ylide (Wittig reagent), a dipolar intermediate with formal opposite charges on adjacent atoms (overall charge neutral). ...
... or ketone and a phosphorus ylide (Wittig reagent), a dipolar intermediate with formal opposite charges on adjacent atoms (overall charge neutral). ...
Homework Set #1
... D-2-deoxyribose is found in DNA. Draw the structure. Deoxyribose and ribose form esters with phosphoric acid in DNA and RNA. Can both monosaccharides react to form the same number of ester combinations? Show the reactive sites for esterfication. CH2OH O ...
... D-2-deoxyribose is found in DNA. Draw the structure. Deoxyribose and ribose form esters with phosphoric acid in DNA and RNA. Can both monosaccharides react to form the same number of ester combinations? Show the reactive sites for esterfication. CH2OH O ...
Dehydration of 2-methylcyclohexanol
... the 2o carbocation can undergo a rearrangement forming a more stable 3 o carbocation. This carbocation can form two products methylenecyclohexane and 1-methylcyclohexene. The product distribution can be under either kinetic or ...
... the 2o carbocation can undergo a rearrangement forming a more stable 3 o carbocation. This carbocation can form two products methylenecyclohexane and 1-methylcyclohexene. The product distribution can be under either kinetic or ...
Document
... Halogenoalkanes undergo nucleophilic substitution reactions. The rates and mechanisms of these reactions depend on whether the halogenoalkane is primary, secondary or tertiary. Explain the term nucleophilic substitution. ...
... Halogenoalkanes undergo nucleophilic substitution reactions. The rates and mechanisms of these reactions depend on whether the halogenoalkane is primary, secondary or tertiary. Explain the term nucleophilic substitution. ...
CHEM 202_ Part 2
... Ketones can be halogenated in acidic or basic medium at alpha carbon. The reaction is the basis of haloform test (iodoform, chloroform, bromoform). The reaction can be used to get carboxylic acids. ...
... Ketones can be halogenated in acidic or basic medium at alpha carbon. The reaction is the basis of haloform test (iodoform, chloroform, bromoform). The reaction can be used to get carboxylic acids. ...
12SN-23-10 OBJECTIVE: Identify how alcohols are classified and
... Identify how alcohols are classified and named. Predict how the solubility of an alcohol varies with the length of its carbon chain. Name the reactions of alkenes that may be used to introduce functional groups. Construct the general structure of an ether and describe how ethers are named. Identify ...
... Identify how alcohols are classified and named. Predict how the solubility of an alcohol varies with the length of its carbon chain. Name the reactions of alkenes that may be used to introduce functional groups. Construct the general structure of an ether and describe how ethers are named. Identify ...
Lecture 2 - UCLA Chemistry and Biochemistry
... Example: Elimination from Cyclohexanol The equilibrium constant for many elimination reactions is low because neither the enthalpy (DH=23.9 kJ, ) nor the entropy (DS=84.91 J, ) changes much and they also display opposing trends. Thus, the equilibrium constant is Keq=1.8 at 25 oC and Keq=8 at 80 oC ...
... Example: Elimination from Cyclohexanol The equilibrium constant for many elimination reactions is low because neither the enthalpy (DH=23.9 kJ, ) nor the entropy (DS=84.91 J, ) changes much and they also display opposing trends. Thus, the equilibrium constant is Keq=1.8 at 25 oC and Keq=8 at 80 oC ...
Chapter 11: Reactions at an sp3 Hybridized Carbon III
... • In this case, however, the stability of tertiary carbocation which results from H– shifting and substituting for CH3OH makes this reaction work with HCl • If tertiary carbocations can be formed then HCl is strong enough to cleave ethers ...
... • In this case, however, the stability of tertiary carbocation which results from H– shifting and substituting for CH3OH makes this reaction work with HCl • If tertiary carbocations can be formed then HCl is strong enough to cleave ethers ...
T. V. RajanBabu Chemistry, 730 Autumn 1997
... Chelated and unchelated transition state models to make all four aldol stereoisomers using diffrent metals Asymmetric catalysis in aldol synthesis : Mukaiyama, Carreira, Evans Ito’s gold-catalyzed aldol reactions (a Knoevenagel-type reaction, see later) of -isocyanoacetates Aldol reactions of ester ...
... Chelated and unchelated transition state models to make all four aldol stereoisomers using diffrent metals Asymmetric catalysis in aldol synthesis : Mukaiyama, Carreira, Evans Ito’s gold-catalyzed aldol reactions (a Knoevenagel-type reaction, see later) of -isocyanoacetates Aldol reactions of ester ...
730-2005 topics
... Chelated and unchelated transition state models to make all four aldol stereoisomers using diffrent metals Asymmetric catalysis in aldol synthesis : Mukaiyama, Carreira, Evans Ito’s gold-catalyzed aldol reactions (a Knoevenagel-type reaction, see later) of -isocyanoacetates Aldol reactions of ester ...
... Chelated and unchelated transition state models to make all four aldol stereoisomers using diffrent metals Asymmetric catalysis in aldol synthesis : Mukaiyama, Carreira, Evans Ito’s gold-catalyzed aldol reactions (a Knoevenagel-type reaction, see later) of -isocyanoacetates Aldol reactions of ester ...
Answer Key to Assignment #7
... 3. Predict the organic product(s) of the following reactions. If more than one organic product is formed, show them all and indicate, if possible, which is/are the major products. Be careful to clearly indicate the relevant stereochemical results (using dashed and wedge bonds where appropriate). If ...
... 3. Predict the organic product(s) of the following reactions. If more than one organic product is formed, show them all and indicate, if possible, which is/are the major products. Be careful to clearly indicate the relevant stereochemical results (using dashed and wedge bonds where appropriate). If ...
aldehydes and ketones
... • Steric factors contribute to the reactivity of an aldehyde. • The carbonyl carbon of an aldehyde is more accessible to the nucleophile because the hydrogen attached to the carbonyl carbon of an aldehyde is smaller than the second alkyl group to carbonyl carbon of a ketone. • Ketones have greater s ...
... • Steric factors contribute to the reactivity of an aldehyde. • The carbonyl carbon of an aldehyde is more accessible to the nucleophile because the hydrogen attached to the carbonyl carbon of an aldehyde is smaller than the second alkyl group to carbonyl carbon of a ketone. • Ketones have greater s ...
Chapter 15 Multistep Syntheses
... • Grouping Chemical Reactions • Retrosynthetic Analysis • Reactions Requiring Both Functional-Group Transformation and Skeletal Construction • Extending the Retrosynthetic Approach: Alternative Routes ...
... • Grouping Chemical Reactions • Retrosynthetic Analysis • Reactions Requiring Both Functional-Group Transformation and Skeletal Construction • Extending the Retrosynthetic Approach: Alternative Routes ...
Dehydration notes-1
... Carbocation intermediate formation. First two steps of the mechanism at the same as for SN1. Carbocation will rearrange for increased stability, if possible. 5. Protons can be removed from any adjacent position leading to multiple products. 6. Major product is the most stable alkene from the most st ...
... Carbocation intermediate formation. First two steps of the mechanism at the same as for SN1. Carbocation will rearrange for increased stability, if possible. 5. Protons can be removed from any adjacent position leading to multiple products. 6. Major product is the most stable alkene from the most st ...
19-3 Esters and Anhydrides (PPT)
... With less basic nucleophiles, especially under acidic conditions, substitution through the addition-elimination mechanism may occur. In the esterification of a carboxylic acid, an alcohol and a carboxylic acid react in the presence of acid to form an ester and water. ...
... With less basic nucleophiles, especially under acidic conditions, substitution through the addition-elimination mechanism may occur. In the esterification of a carboxylic acid, an alcohol and a carboxylic acid react in the presence of acid to form an ester and water. ...
- EdShare - University of Southampton
... Alkenes are unsaturated compounds that can be used in organic synthesis. They can be formed in elimination reactions of halogenoalkanes. An example of this is the reaction between 2-bromopentane and hot ethanolic KOH. Using your knowledge of reaction mechanisms, draw appropriate curly arrows to comp ...
... Alkenes are unsaturated compounds that can be used in organic synthesis. They can be formed in elimination reactions of halogenoalkanes. An example of this is the reaction between 2-bromopentane and hot ethanolic KOH. Using your knowledge of reaction mechanisms, draw appropriate curly arrows to comp ...
- EdShare - University of Southampton
... Alkenes are unsaturated compounds that can be used in organic synthesis. They can be formed in elimination reactions of halogenoalkanes. An example of this is the reaction between 2-bromopentane and hot ethanolic KOH. Using your knowledge of reaction mechanisms, draw appropriate curly arrows to comp ...
... Alkenes are unsaturated compounds that can be used in organic synthesis. They can be formed in elimination reactions of halogenoalkanes. An example of this is the reaction between 2-bromopentane and hot ethanolic KOH. Using your knowledge of reaction mechanisms, draw appropriate curly arrows to comp ...
Catalytic Hydrogenation of Alkenes: Relative Stability of
... Secondary and tertiary alcohols dehydrate by an E1 mechanism. The protonated hydroxy forms an alkyloxonium ion providing a good leaving group: water. Loss of water forms a secondary or tertiary carbocation. Deprotonation forms the alkene. Carbocation side reactions (hydrogen shifts, alkyl shifts, e ...
... Secondary and tertiary alcohols dehydrate by an E1 mechanism. The protonated hydroxy forms an alkyloxonium ion providing a good leaving group: water. Loss of water forms a secondary or tertiary carbocation. Deprotonation forms the alkene. Carbocation side reactions (hydrogen shifts, alkyl shifts, e ...
CN>Chapter 22CT>Carbonyl Alpha
... transfer to water is slow In the reverse direction there is also a barrier to the addition of the proton from water to enolate carbon ...
... transfer to water is slow In the reverse direction there is also a barrier to the addition of the proton from water to enolate carbon ...
Organic Chemistry (I) chapter 3 alkanes
... E. 3-butyl-5,6-dimethyloctane 3. Choose the correct IUPAC name for the following molecule. ...
... E. 3-butyl-5,6-dimethyloctane 3. Choose the correct IUPAC name for the following molecule. ...
Reactions of Alkenes Organic Chemistry
... REACTIONS OVERVIEW Note: These examples were adapted and revised from General, Organic, & Biological Chemistry textbook (with author: Janice Gorzynski Smith) ...
... REACTIONS OVERVIEW Note: These examples were adapted and revised from General, Organic, & Biological Chemistry textbook (with author: Janice Gorzynski Smith) ...
TV RajanBabu Chemistry, 730 Autumn 1997
... Enols, enamines and metalloenamines in synthesis Mechanism of acid and base catalyzed enolization, kinetic vs thermodynamic control Detailed mechanism of -substitution of a carbonyl compound (e. g., bromination) Carbanions as nucleophiles Enolate structure - X-ray structures of enolates, effect of a ...
... Enols, enamines and metalloenamines in synthesis Mechanism of acid and base catalyzed enolization, kinetic vs thermodynamic control Detailed mechanism of -substitution of a carbonyl compound (e. g., bromination) Carbanions as nucleophiles Enolate structure - X-ray structures of enolates, effect of a ...
Wolff rearrangement
The Wolff rearrangement is a reaction in organic chemistry in which an α-diazocarbonyl compound is converted into a ketene by loss of dinitrogen with accompanying 1,2-rearrangement. The Wolff rearrangement yields a ketene as an intermediate product, which can undergo nucleophilic attack with weakly acidic nucleophiles such as water, alcohols, and amines, to generate carboxylic acid derivatives or undergo [2+2] cycloaddition reactions to form four-membered rings. The mechanism of the Wolff rearrangement has been the subject of debate since its first use. No single mechanism sufficiently describes the reaction, and there are often competing concerted and carbene-mediated pathways; for simplicity, only the textbook, concerted mechanism is shown below. The reaction was discovered by Ludwig Wolff in 1902. The Wolff rearrangement has great synthetic utility due to the accessibility of α-diazocarbonyl compounds, variety of reactions from the ketene intermediate, and stereochemical retention of the migrating group. However, the Wolff rearrangement has limitations due to the highly reactive nature of α-diazocarbonyl compounds, which can undergo a variety of competing reactions.The Wolff rearrangement can be induced via thermolysis, photolysis, or transition metal catalysis. In this last case, the reaction is sensitive to the transition metal; silver (I) oxide or other Ag(I) catalysts work well and are generally used. The Wolff rearrangement has been used in many total syntheses; the most common use is trapping the ketene intermediate with nucleophiles to form carboxylic acid derivatives. The Arndt-Eistert homologation is a specific example of this use, wherein a carboxylic acid may be elongated by a methylene unit. Another common use is in ring-contraction methods; if the α-diazo ketone is cyclic, the Wolff rearrangement results in a ring-contracted product. The Wolff rearrangement works well in generating ring-strained systems, where other reactions may fail.