Carbonyls, Aldehydes, Ketones, Organometallic Reagents, IUPAC, Imines, Enamines, Geminal Diols, Hemiacetals, Acetals, Conjugation, Enolate Ions

Most of Quiz 3— Organic chemistry II

Carbonyls (aldehydes/ketones) with primary amines form functional groups, and with secondary amines form functional groups.

Both these reactions follow a modified version of the mechanism

imine, enamine, nucleophilic acyl addition

Carbon-Nitrogen double bonds are generally (stable/unstable/it depends) in the presence of water, so are often (reduced/oxidized/protonated/deprotonated) by (LiAlH4/ NaBH4/ H2 and Pd/ NaBH3CN in pH 2/ H2 and Pd OR NaBH3CN at pH 2/ LiAlH4 OR NaBH4) to give the functional group (imine/ enamine/ amine/ nitrile/ azide) .

stable, reduced, amine

Geminol diols form by hydration of carbonyls in (acid/base/both/neither)

both

geminal diols are (always/sometimes/never) isolatable as pure substances.

NEVER

The geminal diol form predominates over the carbonyl form in solution for (aldehydes/ketones/formaldehyde/none)

formaldehyde only

hemiacetals form in (acid/base/both/neither) conditions

both

Acetals form in (acid/base/both/neither) conditions.

acid

It is (always/sometimes/never) possible to isolate a pure hemiacetal.

sometimes

It is (always/sometimes/never) possible to isolate a pure acetal.

ALWAYS

Hemiacetals form with (1 eq/ 1 eq +/ excess/ catalytic) alcohol present.

1 eq +

Acetals form with (1 eq/ 1 eq +/ excess/ catalytic) alcohol present or a diol.

excess

Conjugated carbonyls have (0/1/2/3) electrophilic carbons.

2

Typically a strongly basic irreversible nucleophile will add to the (C of the C=O/ C alpha to the C=O/ C beta to the C=O/ some other C), this is known as .

C of the C=O (partial positive here makes C=O more electrophilic), 1,2-addition

Which of these is likely to add by 1,4-addition? (select all that apply)

• LiAlH4

• RLi

• NH3

• KCN, HCl

• RMgBr

• CH3CC- (alkynyl anion)

• NaOH

• CH3ONa, CH3OH

NH3; KCN,HCl; NaOH; CH3ONa, CH3OH

(CN-, NH2R, NHR2, OH-, RO-)

Which base will make ~100% enolate from a general ketone? (select all that apply)

• NaOH

• NaH

• NaNH2

• NaOCH3

• (CH3)3COK

• LDA

• DMF

• H2O

• none of these

NaH, NaNH2, LDA

(to produce 100% enolate from a general ketone, base must be significantly stronger than enolate— pKa > 20)

Which is a better acid (lower pKa) at alpha hydrogen: CH3COCH2COCH3 or CH3COCH2CH2CH3

CH3COCH2COCH3 (notice the two C=O on each side)

Which is a better acid (lower pKa) at alpha hydrogen: CH3COCH2CH2CH3 or CH3CH2CH2CH2CH2CHO

CH3CH2CH2CH2CH2CHO (notice C=O at the end, rather than the middle— easier to break)

Which is a better acid (lower pKa) at alpha hydrogen: CH3OCOCH2COOCH3 or CH3COCH2COCH3

CH3COCH2COCH3 (partial + on C=O is greater than partial + on Beta C)