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