Nucleophilic Addition to ketones and aldehydes

what is more reactive ester and ketone or aldehyde

aldehyde

then ketone

and then ester

for griginard addition to esters can the reaction stop at a ketone

no the reaction proceeds to form an alcohol after the ketone is formed.

reactivity of aldehydes and ketones depend on

• sterics

  • less steric hinderenc is more reactive then more steric hinderence

• electrophilicty of carbonyl

  • the carbon is more electrophilc in aldehyde (more reactive) compared to ketones

Mechanisms : basic ideas

in acidic conditions

no strong bases

no - chare

Mechanisms : basic ideas

in basic conditions

no strong acids

no + charge

griginard addition to aldehyde creates what product

secondary alcohol adds 1 R group

griginard addition to ketone creates what product

tertiary alcohol adds 2 R groups

griginard addition to formaldehyde creates what product

primary alcohol 1 R group

what are the conditions for cyanohydrin reactions

mildly acidic

is cyanhydrin reversible raction or not

it is reversible reaction

in Borohydride reduction how does BH4- act like

like H-

borohydride reduction happens in what conditions

it happens in basic conditons

and it has a good nucleophile

the second step in borohydride reaction it needs

an acid work-up like H3O+

borohydride reduction products and reactants

reactants

• aldehyde of ketone

• borohydride (NaBH4)

product

• alcohol

  • aldehyde-primary alcohol

  • ketone-secondary alcohol

imine formation conditions

neutral conditions

• acid is only present in small catalytic amounts

primary amines with ketone or aldhyde gives what product

imine

secondary amines with ketone or aldhyde gives what product

enamine

whats diffrent about its conditions in addition to amines

it is pH sensetive enviornment (4-5) mildly acidic conditions

if ketone is asymetrical where does the double bond get added to make and enamine

the more sub. side

hydration of carbonyls (reactants,prodcuts) and it the reaction reversible

reactants

• aldehyde (more reactive hydration is favored) or ketone (little more difavored due to sterics to bulky) but both can happen

• water with acid catalyst

product

• diol (carbon with OH groups)

yes reaction is reversible and goes back to becoming a carbonyl

carbonyl addition of one equiv alcohol product and environment

hemiacetal (one OH and one OR group) formation needs to have acidic catalyst (H3O+)

D-glucose forms what

cyclic (6 carbon ring) hemiacetal

carbonyl additon of 2 equiv of alcohol products adn enviorment

forms and acetal (2 OR groups on the same carbon) and H20

and a acid catlyst is required