Midterm 1 Review Flashcards
Penultimate carbon
Second to last carbon furthest away from aldehyde
D-Glucose
When OH on penultimate carbon is on the right
L-Glucose
When OH on penultimate carbon is on the left
Anomeric carbon
Carbon bonded to oxygen and OH
Alpha-anomer
When OH on anomeric carbon is axial
Beta-anomer
When OH on anomeric carbon is equatorial
Simple ylides give _ alkenes governed by ___
Z, kinetics
Resonance-stabilized ylides give _ alkenes governed by ___
E, thermodynamics
3 lines substituent
Propyl
4 lines substituent
Butyl
Substituent with 4 lines attached to one carbon
Tert-butyl
IUPAC priorities
Aldehyde > ketone > hydroxy > alkene > alkyne > X, R, OR
Simplest ketone
Acetone
Simplest carbonyl
Formaldehyde
Simplest aldehyde
Acetaldehyde
Benzene ring attached to simple aldehyde
Benzaldehyde
Benzene ring attached to simple ketone
Acetophenone
Gilman reagent reactivity compared to grignard and organolithium reagents
Gilman reagent less reactive, more selective
What reagent(s) would react with epoxides in the presence of acidic functional groups (-OH)?
Gilman reagents, not grignard or organolithium reagents
___ pka predominates
Higher
Carbocation: electrophile or nucleophile?
Electrophile
Carbanion: electrophile or nucleophile?
Nucleophile
Grignard reagents: strong or weak bases?
Strong
Organolithium reagents: strong or weak bases?
Strong
Gilman reagents: strong or weak bases?
Weak
Trans alkene + reagents: CH2I2 Zn(Cu)
Triangle forms where double bond was with anti substituents (one wedge one dash), racemic
Cis alkene + reagents: CH2I2 Zn(Cu)
Triangle forms where double bond was, triangle arms are syn racemic (both wedge or both dash)
Grignard reagent reaction with an epoxide mechanism
C-MgBr bond attacks least substituted carbon, that carbon’s bond to O breaks off O
Arrow label: attack of the nu
Product 2: O shifts over with additional lone pair (now 3) and - charge, substituent excluding MgBr added, MgBr with + charge byproduct, a lone pair on O attacks a proton from given acid whose bond breaks off of its O
Arrow label: add a proton
Product 3: H replaces one of three lone pairs (now neutrally charged), H2O byproduct
What is special about grignard reagent reaction with an achiral meso epoxide?
Achiral meso epoxides are symmetrical, substituent-MgBr can attack from either side, 2 racemic products
Grignard (or organolithium) reagent with an aldehyde or a ketone mechanism
C-MgBr bond attacks carbonyl carbon, that carbon’s bond to O breaks off O
Arrow label: attack of the nu
Product 2: O gains a lone pair (now 3) and - charge and now on a single bond, substituent excluding MgBr now on other side of ex-carbonyl carbon, MgBr with + charge byproduct, a lone pair on O attacks a proton from given acid whose bond breaks off of its O
Arrow label: add a proton
Product 3: H replaces one of three lone pairs (now neutrally charged), H2O byproduct, OH can be on a wedge or dash (racemic)
Key recognition element: -OH group and the new carbon-nucleophile are on the same carbon
Grignard (or organolithium) reagent with an aldehyde or a ketone
How can you make a carboxylic acid with a Grignard reagent?
CO2
Alkyne anion reacting with an aldehyde or ketone mechanism
Lone pair on deprotonated alkyne attacks carbonyl carbon, that carbon’s bond to O breaks off O
Arrow label: attack of the nu
Product 2: O gains a lone pair (now 3) and - charge and now on a single bond, substituent (- charge and lone pair went away) now on other side of electrophilic carbon bound by a wedge or dash (racemic), Na+ byproduct, a lone pair on O attacks a proton from given acid whose bond breaks off of its O
Arrow label: add a proton
Product 3: H replaces one of three lone pairs (now neutrally charged), H2O byproduct, product remains racemic
HCN reacting with an aldehyde or ketone mechanism
Lone pair on deprotonated carbon attacks carbonyl carbon, that carbon’s bond to O breaks off O
Arrow label: attack of the nu
Product 2: O gains a lone pair (now 3) and - charge and now on a single bond, C (- charge and lone pair went away) triple-bonded to N now on other side of electrophilic carbon, a lone pair on O attacks a proton from given acid whose bond breaks off of its bonded atom
Arrow label: add a proton
Product 3: H replaces one of three lone pairs (now neutrally charged), C (with lone pair and - charge) triple-bonded to N byproduct, OH could be on a wedge and H on electrophilic carbon would be on a dash or vice versa (racemic)
After HCN reacting with an aldehyde or ketone mechanism, what happens when you react H2/Ni OR LiAlH4 and H2O?
N becomes NH2, product remains racemic
The Wittig reaction with simple ylide mechanism
Ph3P’s lone pair on P attacks carbon on haloalkane, carbon’s bond breaks off LG atom
Arrow label: simultaneous attack of the nu and departure of the LG
Product 2: Ph3P+ replaces LG and one H on C is suggestively drawn, LG now with four lone pairs and - charge byproduct, lone pair on deprotonated base attacks suggestively drawn H whose bond with C breaks
Arrow label: remove a proton
Product 3: suggestively drawn H goes away and C gains a lone pair and - charge, Li+ byproduct, resonates to Ph3P=CH2
The Wittig reaction with resonance-stabilized ylide mechanism
Lone pair on C attached to Ph3P attacks carbon on resonance-stabilized ylide, carbon’s bond breaks off O
Arrow label: attack of the nu
Product 2: O gains a lone pair and - charge and now single-bonded to C
Arrow label: n/a
Product 3: resonates, bond between C and O points to O, O loses a lone pair and forms a bond with Ph3P (both become neutrally charged), bond between Ph3P and CH2 points to bond between that CH2 and the electrophilic carbon
Arrow label: n/a
Product 4: O- bonded to Ph3P+ leave, double bond forms between electrophilic carbon and CH2
Acid catalyzed hemiacetal and acetal formation from an aldehyde and ketone mechanism
Lone pair on carbonyl oxygen attacks an H, which breaks off O
Arrow label: add a proton
Product 2: byproduct and major product form. Carbonyl double bond points to carbonyl O and resonates to give O a lone pair. Lone pair on nucleophile attacks carbocation.
Arrow label: attack of the nu
Product 3: major product forms, lone pair on given base removes an H from ex-nucleophile
Arrow label: remove a proton
Product 4 (hemiacetal intermediate): byproduct and major product form, lone pair on O from carbonyl steals a proton
Arrow label: add a proton
Product 5: byproduct and major product form, arrow drawn for H2O LG to leave
Arrow label: departure of the LG
Product 6: H2O leaves, + charge where LG broke off, O lone pair points to its bond with carbocation, resonates to double bond and + charge moves to O, lone pair on new given nucleophile attacks ex-carbocation which breaks off the O it is double-bonded to
Arrow label: attack of the nu
Product 7: major product forms, given base steals proton from newly-added nucleophile
Arrow label: remove a proton
Product 8: byproduct and major product form
Why no SN2 (attack of nu rather than remove a proton) in the last step of acid catalyzed hemiacetal and acetal formation from an aldehyde and ketone?
Because of sterics
Acid catalyzed formation of cyclic hemiacetal mechanism
Electrophilic oxygen steals proton
Arrow label: add a proton
Product 2: byproduct and major product form, lone pair on OH (not double-bonded) attacks more electrophilic carbon, one of the double bonds goes back to oxygen
Arrow label: attack of the nu
Product 3: ring forms, given base removes a proton
Arrow label: remove a proton
Product 4: byproduct and major product form, racemic about OH (where the double bond O was)
Base-catalyzed formation of a hemiacetal mechanism
Lone pair on base removes a proton attached to O
Arrow label: remove a proton
Product 2: byproduct and major product form, deprotonated oxygen attacks given electrophilic carbon, double bond gives oxygen a lone pair
Arrow label: attack of the nu
Product 3: O- attacks given proton
Arrow label: add a proton
Product 4: byproduct and major product form, asterisk on chiral center
Carbon radical: electrophile or nucleophile?
Electrophile
Carbene: electrophile or nucleophile?
Both
Primary OH + PCC
Aldehyde
Secondary OH + PCC or H2CrO4
Ketone
Alkene + 1) O3
2) (CH3)2S
Ozonolysis
Terminal alkyne + 1) (sia)2BH
2) H2O2, NaOH
Aldehyde on terminal carbon, carbon chain of single bonds
Terminal alkyne + HgSO4
H2SO4, H2O
Ketone on internal (most substituted) carbon from alkyne, carbon chain of single bonds
Alkene + 1) BH3
2) H2O2, NaOH
Non-Markovnikov OH
Alkene + H2O (or ROH)
Cat H2SO4
Markovnikov OH (or -OR)
Alkene + 1) Hg(OAc)2, H2O
2) NaBH4
Racemic Markovnikov OH
Alkene + HBr
Markovnikov Br
Alkene + Br2
Br on both carbons, racemic anti product
Br on both carbons racemic anti product + 1) 3NaNH2
2) H3O+
Brs go away and in between those, an alkyne forms
Alkene + 1) OsO4
2) NaHSO3
OH on both carbons, racemic syn product
Alkene + H2/Pd
Alkane syn product
Alkene + Br2
H2O
OH on the most substituted carbon, Br on the least substituted carbon, racemic anti product
OH on the most substituted carbon Br on the least substituted carbon racemic anti product + NaOH
Racemic syn epoxide
Alkene + RCO3H
mCPBA
Racemic syn epoxide
Alkene + NBS, hv
Double bond moves away one to be more stable, Br adds to least substituted carbon (allylic bromoalkene)
Alkene + HBr
H2O2
Non-Markovnikov Br
Alkene + 1) OsO4
2) NaHSO3
OH on both carbons, racemic syn product
Br on both carbons racemic anti product + 3NaNH2
Brs go away and in between those, a deprotonated alkyne forms
Internal alkyne + H2
Lindlar
Cis alkene
Internal alkyne + Na°
NH3
Trans alkene
Carbon chain of single bonds with primary Br + E2
tBuOK
Br goes away, double bond forms between the carbon Br was connected to and the carbon next to it
Secondary or tertiary Br + tBuOK
E2
Br goes away, double bond forms between the carbon Br was connected to and the least substituted carbon (non-Zaitsev)
Secondary Br + E2
NaOH
Br goes away, double bond forms between the carbon Br was connected to and the most substituted carbon
Primary Br + NH3
SN2
NH2 substitutes Br
Primary OH + PBr3
SN2
Br substitutes OH
Secondary OH + SOCl2
pyridine
Cl substitutes OH and stereochemistry inverted
Tertiary OH + HBr
SN2
Br substitutes OH
Primary OH + conc H2SO4
E2
OH goes away, double bond forms between the carbon OH was connected to and the carbon next to it *double bond could resonate to be more stable
Primary OH + H2CrO4
Double bond O added to carbon next door to OH
Syn epoxide + NH3
NH2 added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + NaOH
OH added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + NaOCH3
OCH3 added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + NaCN
CN added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + 1) LiAlH4
2) H3O+
H added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + NaN3
N3 added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + 1) RC [triple bond] C : -
2) H3O+
Substituent added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + 1) C-C-MgBr
2) H3O+
Ethyl added to least substituted carbon in an anti fashion, O from epoxide becomes OH and retains stereochemistry
Syn epoxide + CH3OH
Cat H2SO4
O from epoxide becomes OH on least substituted carbon and retains stereochemistry, OCH3 added to most substituted carbon in an anti fashion, methyl on most substituted carbon gets its stereochemistry inverted
Syn epoxide + H2O
Cat H2SO4
O from epoxide becomes OH on least substituted carbon and retains stereochemistry, OH added to most substituted carbon in an anti fashion, methyl on most substituted carbon gets its stereochemistry inverted
Br on both carbons racemic anti product + 2NaNH2
Internal alkyne
Alkane + Br2
hv or heat
Br added to most substituted carbon
Alkene + HBr
ROOR hv or heat
Br added to least substituted carbon of double bond, and double bond goes away
Secondary OH + H2SO4
Double bond forms between carbon OH was attached to and the carbon next to it, OH goes away
Key recognition element: what does the formation of a carbon-carbon double bond mean?
Wittig Reaction
Primary Br + 1) Ph3P
2) butylLi
+PPh3 substitutes Br, lone pair and - charge on the carbon next to it
Carbonyl reactant + H2O <-> hydrate product
Which side predominates?
Side with less sterics predominates
When Fs are present in carbonyl reactant + H2O <-> hydrate product, which side predominates?
Product side predominates because carbonyl carbon is more electrophilic and inductive effects
What reagents do Grignard reagents react with?
Epoxides, aldehydes/ketones
What reagents do organolithium reagents react with?
Epoxides, aldehydes/ketones
What reagents do Gilman reagents react with?
Epoxides, 1° and 2° alkyl halide
