ACS Organic Chemistry Exam Study Set ACS Organic Chemistry Exam Study Set Organic Chemistry ACS Exam Set 2024 Ques-
tions and Answers When naming carboxylic acids - ANSfind the longest continuous carbon atom chain contianing the carboxylic acid group What is the prefix in carboxylic acids? - ANS -oate To name an ester, - ANSidentify the alkyl group that is in the 'alcohol' portion of the molecule and name it; then identify the acid part of the molecule. The ester is named with the alkyl part first, and the acid part is named as a carboxylate. The terms ortho, meta, and para are used when benzene derivatives possess - ANSexact 2 subsitu-
ents Is a structure with more or less covalent bonds more stable? - ANSMore covalent bonds is more sta-
ble What is the dow nside to separation of charges? - ANSSeparation of charges cost energy and results in a less stable resonance contributor What does the nitrate ion look like lewis structure? - ANS The bonding pi orbital is lower in energy than antibonding orbital (T/F)? - ANSTrue The sigma orbital is lower in energy than the pi orbital (T/F)? - ANSTrue How do you prepare epoxides? - ANSReagent is peracid (COOOH) ; alkene to an epoxide; main-
tain stereochemistry What are the reagents of hydroboration of alkenes? - ANSBH 3, Et2O What is anti -markovnikov? - ANSWhen the H adds to the carbon with the fewest attached hydro-
gens What is syn - ANSH and B add to the same face of the alkene. What is markovnikov? - ANSHalide component of HX bonds adds to the more highly substitue d carbon, whereas the hydrogen prefers the carbon which already contains more hydrogens. What is aromatic sulfonation? - ANSreagent is h2so4, heat or so3 (fuming h2so4) What is an activating group? - ANSOrtho or para directing What is a deactivating gro up? - ANSmeta directing What are examples of activating EDG? - ANSO, NR2, NH3, OH, OR, NHCOR, OCOR, R, BEN-
ZENE, C=CR2, ACS Organic Chemistry Exam Study Set What are deactivating EWG? - ANS -X, COH, COR, COOR, COOH, COCL, CF3, CN, HSO3 -, NH3+ NR3+, NO2+ EDG ______ the rate of reaction - ANSincrease EWG ________ the rate of reaction - ANSdecrease What are resonance effects? - ANSThose that occur through the pi system and can be represented by resonance structures What are inductive effects? - ANSThose that occur through the sigma system due to electronega-
tiveity type effects. What does EDG do? - ANSAtoms adjacent to the pi system activate the aromatic ring by increasing the electron density on the ring through a resonance donating effect. (ortho -para directing) What does an EWG do? - ANSEWGs with pi bonds to electronegative atoms adjacent to the pi sys-
tem deactivate the aromatic ring by decreasing the electron density on the ring through a resonance withdrawing effect. (meta directing) Halogens are deacitvaitng but have both - ANSinduc tive electron withdrawing and resonance donat-
ing (electronegativity and lone pair donation) What is the aldol condensation reaction? - ANSreaction in which an enol or an enolate ion reacts with a carbonyl compound to form a beta hydroxyaldehyde or b -hydro xyketone, followed by dehy-
dration to give a conjugated enone. How does one transform a fischer projection into a cyclic ring in chair conformation? - ANSFreely rotate the bonds (change the position of the OH and CH2OH in the fischer projection, then the oyxgen -H bond will nucleophilically attack the carbon, kick the double bond of the oxygen to the oxygen to form an oxygen anion and then get protonated by a hydrogen from the alcohol gorup used to nucleophilically attack the carbon. (mechanism is in noteboo k) What reaction uses BuLi? - ANSCorrey Fuches What is the starting and end product of the Ph3P, Br - ? - ANSketone; alkene What is LiAlh4? - ANSA reducing agent; carboxylic acid and ester can be reduced by this in add-
tiiton to aldehydes or ketones What happens in a free -radical additon of H -Br to alkenes? (HBr RO -OR) - ANSantiadditon or syn addition of H and Br. Antimarkovnikov. Enolate (ester) --> ketone - ANSNaOEt --> PhCh2Br --> H3O+, heat (Remove CO2) What is saponification? - ANSis the alkaline h ydrolysis of the fatty acid esters. Example: The chemical reaction between any fat and sodium hydroxide is a saponification reaction. triglyceride + sodium hydroxide (or potassium hydroxide) → glycerol + 3 soap molecules Carbonyl attack ACS Organic Chemistry Exam Study Set What is a Grignar d reagent? - ANSan organometallic chemical reaction in which alkyl, vinyl, or aryl-magnesium halides (Grignard reagents) add to a carbonyl group in an aldehyde or ketone. This reaction is an important tool for the formation of carbon -carbon bonds. How do you prepare a Grignard reagent? - ANSTreat magnesium, and then you treat the Grignard with a strong acid. This gives you the alkane. You can also use this to introduce deuterium (D) into molecules! The first step is to make the Grignard reagent What's a d ecoupled HNMR? - ANSshows no splitting at all; it consists of a set of single peaks, one for each carbon or each set of equivalent carbons in a molecule. (EXAMPLE in the exam is that benzene is basically meso, so the signals must be individual 6 signals on their own. What are the reagents of the Claisen condensation? - ANSclaisen condensation between esters con-
taining alpha hydrogens, promoted by a base such as sodium thoxide, affords beta keto esters. (use stronger bases to increase yield: NaH) The redu cing agent: NaBH4 reduces? - ANSAldehydes and Ketones The reducing agent: LiAlH4 reduces - ANSCarboxylic acids and esters Why can LiAlH4 reduce more? - ANSBecause the Al -H bond is weaker and thus less stable than B -
H bond. When using LiAlH4 to reduced a mides what happens? (h2o workup) - ANSRCH2NH2 How does one form an epoxide? - ANSFrom C=C to epoxide ; ring closure forms via a intramolec-
ular SN2 reaction. What is the chemical properties of an epoxide? - ANSCylic ether with a three atom ring; ring ap-
proximates an equilateral triangle ; making it pretty reactive, more than other ethers produced on a large scale. What reagents are used to form an epoxide? - ANSmCPBA or a base What is PCC in DCM? - ANSUsed in oxidation of primary alcohols to aldehydes; a nd oxidation of secondary alcohols to ketones ; usually used to oxidize alcohols into carbonyl compounsd What is the Wittig reaction? - ANSReaction which involves the reaction of an aldehyde or ketone; The phosphoran (PH3P= CR3R4 can be used to produce an alkene, but then proceed to form an un-
stable 4 membered ring. What happens after phosphonium ylide is added to a ketone or aldehyde? - ANSAlkene CH2 is formed; PH3P=O by product. What happens when MCPBA is added to an alkene? - ANSForms into an epoxide!! What happens when an workup is applied to an epoxide? - ANSOH OH; BREAKS apart the ether Why do we use AlCl3 in Friedel Crafts - Alkylation? - ANSGood lewis acid catalyst
tions and Answers When naming carboxylic acids - ANSfind the longest continuous carbon atom chain contianing the carboxylic acid group What is the prefix in carboxylic acids? - ANS -oate To name an ester, - ANSidentify the alkyl group that is in the 'alcohol' portion of the molecule and name it; then identify the acid part of the molecule. The ester is named with the alkyl part first, and the acid part is named as a carboxylate. The terms ortho, meta, and para are used when benzene derivatives possess - ANSexact 2 subsitu-
ents Is a structure with more or less covalent bonds more stable? - ANSMore covalent bonds is more sta-
ble What is the dow nside to separation of charges? - ANSSeparation of charges cost energy and results in a less stable resonance contributor What does the nitrate ion look like lewis structure? - ANS The bonding pi orbital is lower in energy than antibonding orbital (T/F)? - ANSTrue The sigma orbital is lower in energy than the pi orbital (T/F)? - ANSTrue How do you prepare epoxides? - ANSReagent is peracid (COOOH) ; alkene to an epoxide; main-
tain stereochemistry What are the reagents of hydroboration of alkenes? - ANSBH 3, Et2O What is anti -markovnikov? - ANSWhen the H adds to the carbon with the fewest attached hydro-
gens What is syn - ANSH and B add to the same face of the alkene. What is markovnikov? - ANSHalide component of HX bonds adds to the more highly substitue d carbon, whereas the hydrogen prefers the carbon which already contains more hydrogens. What is aromatic sulfonation? - ANSreagent is h2so4, heat or so3 (fuming h2so4) What is an activating group? - ANSOrtho or para directing What is a deactivating gro up? - ANSmeta directing What are examples of activating EDG? - ANSO, NR2, NH3, OH, OR, NHCOR, OCOR, R, BEN-
ZENE, C=CR2, ACS Organic Chemistry Exam Study Set What are deactivating EWG? - ANS -X, COH, COR, COOR, COOH, COCL, CF3, CN, HSO3 -, NH3+ NR3+, NO2+ EDG ______ the rate of reaction - ANSincrease EWG ________ the rate of reaction - ANSdecrease What are resonance effects? - ANSThose that occur through the pi system and can be represented by resonance structures What are inductive effects? - ANSThose that occur through the sigma system due to electronega-
tiveity type effects. What does EDG do? - ANSAtoms adjacent to the pi system activate the aromatic ring by increasing the electron density on the ring through a resonance donating effect. (ortho -para directing) What does an EWG do? - ANSEWGs with pi bonds to electronegative atoms adjacent to the pi sys-
tem deactivate the aromatic ring by decreasing the electron density on the ring through a resonance withdrawing effect. (meta directing) Halogens are deacitvaitng but have both - ANSinduc tive electron withdrawing and resonance donat-
ing (electronegativity and lone pair donation) What is the aldol condensation reaction? - ANSreaction in which an enol or an enolate ion reacts with a carbonyl compound to form a beta hydroxyaldehyde or b -hydro xyketone, followed by dehy-
dration to give a conjugated enone. How does one transform a fischer projection into a cyclic ring in chair conformation? - ANSFreely rotate the bonds (change the position of the OH and CH2OH in the fischer projection, then the oyxgen -H bond will nucleophilically attack the carbon, kick the double bond of the oxygen to the oxygen to form an oxygen anion and then get protonated by a hydrogen from the alcohol gorup used to nucleophilically attack the carbon. (mechanism is in noteboo k) What reaction uses BuLi? - ANSCorrey Fuches What is the starting and end product of the Ph3P, Br - ? - ANSketone; alkene What is LiAlh4? - ANSA reducing agent; carboxylic acid and ester can be reduced by this in add-
tiiton to aldehydes or ketones What happens in a free -radical additon of H -Br to alkenes? (HBr RO -OR) - ANSantiadditon or syn addition of H and Br. Antimarkovnikov. Enolate (ester) --> ketone - ANSNaOEt --> PhCh2Br --> H3O+, heat (Remove CO2) What is saponification? - ANSis the alkaline h ydrolysis of the fatty acid esters. Example: The chemical reaction between any fat and sodium hydroxide is a saponification reaction. triglyceride + sodium hydroxide (or potassium hydroxide) → glycerol + 3 soap molecules Carbonyl attack ACS Organic Chemistry Exam Study Set What is a Grignar d reagent? - ANSan organometallic chemical reaction in which alkyl, vinyl, or aryl-magnesium halides (Grignard reagents) add to a carbonyl group in an aldehyde or ketone. This reaction is an important tool for the formation of carbon -carbon bonds. How do you prepare a Grignard reagent? - ANSTreat magnesium, and then you treat the Grignard with a strong acid. This gives you the alkane. You can also use this to introduce deuterium (D) into molecules! The first step is to make the Grignard reagent What's a d ecoupled HNMR? - ANSshows no splitting at all; it consists of a set of single peaks, one for each carbon or each set of equivalent carbons in a molecule. (EXAMPLE in the exam is that benzene is basically meso, so the signals must be individual 6 signals on their own. What are the reagents of the Claisen condensation? - ANSclaisen condensation between esters con-
taining alpha hydrogens, promoted by a base such as sodium thoxide, affords beta keto esters. (use stronger bases to increase yield: NaH) The redu cing agent: NaBH4 reduces? - ANSAldehydes and Ketones The reducing agent: LiAlH4 reduces - ANSCarboxylic acids and esters Why can LiAlH4 reduce more? - ANSBecause the Al -H bond is weaker and thus less stable than B -
H bond. When using LiAlH4 to reduced a mides what happens? (h2o workup) - ANSRCH2NH2 How does one form an epoxide? - ANSFrom C=C to epoxide ; ring closure forms via a intramolec-
ular SN2 reaction. What is the chemical properties of an epoxide? - ANSCylic ether with a three atom ring; ring ap-
proximates an equilateral triangle ; making it pretty reactive, more than other ethers produced on a large scale. What reagents are used to form an epoxide? - ANSmCPBA or a base What is PCC in DCM? - ANSUsed in oxidation of primary alcohols to aldehydes; a nd oxidation of secondary alcohols to ketones ; usually used to oxidize alcohols into carbonyl compounsd What is the Wittig reaction? - ANSReaction which involves the reaction of an aldehyde or ketone; The phosphoran (PH3P= CR3R4 can be used to produce an alkene, but then proceed to form an un-
stable 4 membered ring. What happens after phosphonium ylide is added to a ketone or aldehyde? - ANSAlkene CH2 is formed; PH3P=O by product. What happens when MCPBA is added to an alkene? - ANSForms into an epoxide!! What happens when an workup is applied to an epoxide? - ANSOH OH; BREAKS apart the ether Why do we use AlCl3 in Friedel Crafts - Alkylation? - ANSGood lewis acid catalyst
