Organic :( Flashcards
Nucleophilic addition HOMO?
Nucleophile lp
NA LUMO?
C=O pi*
NA hard or soft nucleophile?
Hard (electrostatic attraction important)
NA mechanism
See notes
What is the Burgyl-Dunitz trajectory?
approach of nucleophile 107 degrees to c=o bond
Draw out reasons for ideal angle of nucleophile approach
See notes
Large bulky R groups effect on reactivity
Reduced, increase steric crowding
e- withdrawing groups effect on reactivity
higher, increase electrostatic attraction
water reacts with HCOCCl3 mechanism
see notes
RC=OR’ (NaCN, EtOH) -> R’RC(CN)(OH)
see notes
NaHSO3 nucleophilic attack draw mechanism
see notes
Addition of hydride to carbonyl what is source of nucleophilic hydrogen?
B-H or Al-H bonds
HOMO and LUMO hydride addition?
HOMO BHsigma LUMO C=O pi*
Draw general hydride addition reaction
see notes
Hydride: aldehydes reduced to…
primary alcohol
Hydride: ketones reduced to…
secondary alcohol
Speed of aldehyde vs ketone reduction?
aldehyde faster, less steric crowding, less sigma donation
Most convenient hydride reagent?
NaBH4 - reduces aldehydes and ketone ONLY (mildest reagent for job)
Reactions often carried out in protic solvent so can be source of >1 hydride so less than 1 equivalent can be used
In organometallic reagents c-metal bond is…
polarised towards carbon so carbon is a nucleophilic centre
How do you prepare Grignard reagent?
see notes
How do you prepare organolithium?
see notes
R-metals…
are powerful carbon nucleophiles, attack carbonyl groups of aldehydes/ketones to make alcohols (and form new C-C bond!)
