Exam 1 - Reaction Questions Review

nucleophiles

R-, CNH2, COH, alkene

electrophiles

carbocation, LG (X, OH2+, OTs), carbonyl (tetrahedral intermediate)

base

KOTBU, NaH

acids

H2SO4, HX

order of leaving group strength - pick FIRST - cannot be what was added

X, OR, OH, NR2, NH2

order of kicking group strength -pick SECOND

O-, OH, OR, NH2, NR

steps for rxn with nuc and e+

1) identify nuc and e+

2) nuc attack e+

steps for rxn with nuc, e+, and acid (forming TI)

1) identify nuc, e+, and acid

2) acid protonates e+ (always on actual atom, not C)

3) nuc attack e+

steps for rxn with nuc, e+, and base (forming TI)

1) identify nuc, e+, and base

2) base deprotonates nuc

3) nuc attack e+

3 parts of HNMR

integration, splitting, shift

integration with HNMR

number of hydrogens attached to a carbon + number of symmetrical hydrogens (DONT FORGET SYMMETRY)

splitting with HNMR

number of hydrogens attached to nextdoor carbons + 1

1-3 shift with HNMR

normal C-H bonds

3-5 shift with HNMR

H attached to a C thats attached to an EN atom (Cl,Br,O,N)

5-7 shift with HNMR

H attached to a carbon in a double bond

7-9 splitting with HNMR

hexane involved

9-10.5

hydrogen attached to a carbonyl

10.5-12

OH attached to carbonyl

things to remember with HNMR

when choosing which molecule

• pay attention to symmetry

when drawing a molecule…

• don’t forget pentanes

• OH and NH2 doesn’t show correctly on HNMR

• pay attention to shift and integration to write out parts of a molecule, then consider shifting

step 1 for carbon NMR

draw line at 100

right is sp/sp3

left is sp2

sp3 carbons are

attached to four things

sp2 carbons have a

double bond (attached to three things)

sp carbons have a

triple bond (linear)

step 2 for carbon NMR

count number of sp3 peaks on NMR and number of sp3 peaks in each molecule, match, process of elimination

tetrahedral intermediate to carbonyl steps

1) identify KG and LG

2) KG kicks, LG leaves

don’t forget that in some TI questions there will

NOT be a leaving group

forming carbonyls… what do do when you see that the kicking group has a positively charged oxygen?

bring in the water molecule step

forming TI with the water molecule step

1) identify KG and LG

2) draw OH2 with its electrons

3) OH2 takes a H from KG

4) draw H—OH2

5) give H to LG so it has a reason to leave

6) KG kicks, LG leaves

two mass spec peaks to know

wide and low OH peak at 3200

narrow and low C=O peak at 1700