4. Haloalkanes & Alkyl Halides Flashcards
what is the classification of 1/2/3 haloalkanes based on
how many C are bonded to the C attached to the halogen
what are the 2 methods of preparing alkyl halides
halogenation of alkene
halogenation substitution with alcohol
what are the reagents involved when preparing alkyl halides from alkenes
HX or X2
what are the reagents involved when preparing alkyl halides from alcohols
SOCl2 or HX
what are the 2 reaction types that alkyl halides can undergo
substitution
elimination
how are Grignard reagents formed
alkyl or aryl halide + Mg/ether solvent
what is the reaction rate equation for Sn1
rate ~ [alkyl halide]
doesnt depend on [nucleophile]
what is the reaction rate equation for Sn2
rate ~ [alkyl halide] [nucleophile]
what classification of alkyl halides does Sn1 mechanism favour
3 > 2»_space; 1
favours more stable carbocations like 3
what classification of alkyl halides does Sn2 mechanism favour
1 and some 2
not 3
what is the stereochemistry involved in Sn1 mechanism
starting with either enantiomer always gives a racemic mix
what is the stereochemistry involved in Sn2 mechanism
chiral non racemic mix of alkyl halide leads to inversion of configuration resulting in chiral non racemic product
what reaction does E1 compete with
Sn1
what conditions favor E1 over Sn1
in terms of pH, temp and solvents
strong base
high temp
non nucleophilic solvent
what is the rate equation of E1
rate ~ [alkyl halide]
what is the rate equation of E2
rate ~ [alkyl halide] [nucleophile]
what classification of alkyl halides does E2 mechanism favour
3 > 2»_space; 1
can do 1 if it extends conjugation
what does E2 mechanism require in terms of pH
strong base
what mechanism will the reaction occur by if:
the alkyl halide is 1
the nucleophile is weak (eg H2O and CH3OH)
SN2
what mechanism will the reaction occur by if:
the alkyl halide is 1
the nucleophile is low basicity and stronger Nu (eg Cl-, Br-, I-, CH3COO-)
SN2
what mechanism will the reaction occur by if:
the alkyl halide is 1
the nucleophile is high basicity and strong Nu (eg OH-, NH3, CH3O-)
SN2
what is the general reaction mechanism for all 1* alkyl halides
Sn2
what mechanism will the reaction occur by if:
the alkyl halide is 2
the nucleophile is weak (eg H2O and CH3OH)
SN1 or SN2
what mechanism will the reaction occur by if:
the alkyl halide is 2
the nucleophile is low basicity and stronger Nu (eg Cl-, Br-, I-, CH3COO-)
SN2
