Flashcards in Block 6: Functional Groups II Deck (118)
How does ethanol act as a base?
CH3CH2OH + Na+NH2- --> CH3CH2O-Na+ + NH3
How does ethanol act as an acid?
CH3CH2OH + H2SO4 ---> CH3CH2OH2 + HSO4-
What is the conjugate base of an alcohol called?
An alkoxide ion
What is the conjugate acid of an alcohol called?
An oxonium ion
Why are the alkoxide and oxonium ions important?
They act as EXCELLENT nucleophiles and electrophiles in the synthesis of organic compounds
Are phenols acidic or basic?
Phenols are vaguely acidic as their conjugate base in an electron donating group, causing the ring to become resonance stabilized.
How do electron withdrawing groups affect the acidity of a phenol?
They make it more acidic as they stabilize the phenoxide anion further
How do electron donating groups affect the acidity of a phenol?
They make it less acidic as they destabilze the phenoxide anion
How do you know whether an alcohol will react via Sn1 or Sn2?
Same rule as for haloalkanes
How can alcohols be prepared?
Alkyl Halide Hydrolysis
Acid catalysed addition of H2O
Reduction of aldehyde/ketone/ester
Grignard reagents with Methanal, other aldehydes, ketone, esters or acyl chlorides.
What is the mechanism of an alcohol being formed via alkyl halide hydrolysis?
CH3Br + OH- --> CH3OH + Br- (Sn2)
(CH3)3CCl +H2O --> (CH3)3C+ +Cl --H2O--> (CH3)3CO+H2 --- -H --> (CH3)3COH + HCl
What is the mechanism of an alcohol being formed via acid catalysed addition of H2O?
CH3CH=CH2 + H2O ---(H+) --> CH3CH(OH)CH3 + CH3CH2CH2OH
What reagent do you use if you want the minor product of an addition reaction with alcohol?
What is the mechanism of an alcohol being formed via hydroboration oxidation?
CH3CH=CH2 ---(B2H6/H+)--> CH3CH2CH2BrH2 ---> CH3CH2CH2OH
What does an aldehyde reduce to?
What does a ketone reduce to?
What does an ester reduce to?
2x primary aclohols
What are the reagents you could use to reduce an aldehyde/ketone/ester?
LiAlH4 or NaBH4 with H3O+
What is formed when methanal reacts with a grignard reagent?
Primary alcohol with an extra carbon
What is formed when an aldehyde other than methanal reacts with a grignard reagent?
What is formed when a ketone reacts with a grignard reagent?
What is formed when an ester or acid chloride reacts with a grignard reactant?
A tertiary alcohol is formed with 2 identical R groups.
What are the ways in which new C bonds can be formed?
Grignard reagents, nitriles, and alkynides (Grignard most likely)
What are the reactions an alcohol can perform?
What reagents are needed for an alcohol to form a haloalkane?
Addition of SOCl2 (if primary or secondary) or HCl (if tertiary)
What is the mechanism of Sn1 and Sn2 alcohol substitution?
CH3OH --(SOCl2) --> CH3Cl
(CH3)3COH + HCl --> (CH3)3CCl + H2O
What reagents are needed for an alkoxide to form an ether?
CH3CH2O- + RX --> CH3CH2COR + X-
What reagent is needed to form an alkene from an alcohol?
Concentrated H2SO4 and Heat.
Why does the alcohol have to be protonated (unlike the haloalkane) to form an alkene?
Because OH on its own is a poor leaving group, but H2O is very good.