Exam 2 - Reduction and Hemiacetal Formation Flashcards

1
Q

___-mediated hemiacetal formation is MORE common than ___-mediated hemiacetal formation.

A

Acid-mediated is more common than Base-mediated.

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2
Q

A ketone/aldehyde + ___ will create a hydrate.

A

H2O

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3
Q

In Base-mediated hemiacetal formation, you react a ketone with ___ and ___ in order to make the hemiacetal.

A

ketone, ethanol, Na(+) (-)OR

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4
Q

Basic conditions: Intermediates must be ___/___ charged.

A

neutral/negatively charged

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5
Q

A ___ is when OH and OR are on the same C.

A

hemiacetal

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6
Q

___ conditions: Intermediates must be neutral/positively charged.

A

Acidic conditions

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7
Q

*Note: Oxygen nucleophiles are ___ nucleophiles.

A

weaker nucleophiles

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8
Q

You can also add alkynes to ketones/aldehydes by adding ___ with a separate H3O+ acidic workup step afterward. This will create a new ___ group added on the central C, with the O becoming a ___.

A

Na(+) (-)alkyne-R, alkyne-R, OH

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9
Q

You can also add CN to ketones/aldehydes by adding ___ and ___. This will create a new ___ group added on the central C, with the O becoming a ___.

A

Na(+) (-)CN, H2O, CN, OH

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10
Q

In Acid-mediated hemiacetal formation, you can also use ___ instead of HCl with the ketone and ethanol.

A

pTsOH

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11
Q

A ___ is when two OHs are on the same C.

A

hydrate

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12
Q

Acidic conditions: Intermediates must be ___/___ charged. However, ___ ___ are okay.

A

neutral/positively charged, however non-basic anions (i.e. Br-, Cl-, etc.) are okay

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13
Q

A hydrate is when two ___ are on the same ___.

A

two OHs on the same C.

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14
Q

___ conditions: Intermediates must be neutral/negatively charged.

A

Basic conditions

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15
Q

Ketones are generally ___ stable than aldehydes.

A

more

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16
Q

A hemiacetal is when ___ and ___ are on the same ___.

A

OH and OR on the same C

17
Q

In Acid-mediated hemiacetal formation, you react a ketone with ___ and ___ in order to make the hemiacetal.

A

ketone, ethanol, HCl

18
Q

When a Ketone reacts with H2O, only 0.1% of the product is a hydrate. When Formaldehyde reacts with H2O, 99.9% of the product is a hydrate. This is because Cs have more ___ ___ (___ ___), so they cannot move as close to each other.

A

steric clash (are bigger)

19
Q

A ketone/aldehyde + H2O will create a ___.

A

hydrate

20
Q

Ketones are generally more stable than aldehydes because of more ___ and more ___ from ___ bonds.

A

more conjugation, more donation from C-H bonds