Synthetic transformations part 2

Question 1

HX on an alcohol

Answer 1

X replaces alcohol
makes H2O
R-CH2-OH to R-CH2-X
halogenation of alcohol (X= Cl, Br, I)

Question 2

SOCl2 (mild base, poor nucleophile, pyridine)

Answer 2

Cl replaces alcohol
halogenation of alcohol
R-CH2-OH to R-CH2-Cl

Question 3

PBr3 (mild base, poor nucleophile, pyridine)

Answer 3

Br replaces alcohol
Halogenation of alcohol
R-CH2-OH to R-CH2-Br

Question 4

Any common nucleophile

Answer 4

replaces LG(leaving group) attached to carbon with Nucleophile
R-CH2-LG to R-CH2-Nuc
SN2 rxn

Question 5

What are Common nucleophiles

Answer 5

Best: RS-, NC-. I-, PR3, R3C-, R2N-, RC-trip bond-C-, RO-
Good: Br-, R2S, NR3, Cl-, RCO2-, N3-
Poor: strong acids, F-, HCO3-, R2O

Question 6

NaOH or KOH

Answer 6

replaces leaving group with OH
R-CH2-LG to R-CH2-OH
SN2 rxn

Question 7

Na metal + ROH = NaOR (sodium alcohol)

Answer 7

replaced LG with OR
R-CH2-LG to R-CH2-OR
SN2 rxn

Question 8

NaNH2 (any strong base) + R-CH2-LG

LG = Cl, Br, I, OTs

Answer 8

R- C triple bond C-CH2-R
create triple bonded CC
SN2 rxn

Question 9

What are Common Leaving groups

Answer 9

Great: RSO3- (R= CF, tol, CH3)
Good: R2O ( H2O, OH, ether)
Poor: Strong bases, F-, RO-, R2N-, R3C-

Question 10

E2 Small base

Answer 10

zaitsev elimination
most substituted c gets double bond
due to small molecule

Question 11

E2 big base

Answer 11

hoffman elimination
least sub c gets double bond
more easily accessible
steric hindrance