Question

Select the best reagent that will promote the following transformation. OSO2CH3 N3 (R)-CH3CHCH2CH3 (S-CH3CHCH2CH3 O NaN3, DMF O NaN3, MeOH O IN3, DMF O HN3, MeOH

Answer 1

oso2CH3 NaN3 N3 CH3-CH-C H2-CH3 CH3-CH-CH2-CH3 DMF In this substitution reaction, the configuration of the product is inverted. So this must be SN2 reaction We know that the solvent plays an important role in these SN reactions. Polar protic solvents ( like alcohols) favors SN1 reaction, in which ionization takes place Polar aprotic solvents ( like DMSO, SMF, ether) favors SN2 reaction. So from the given options A and C have the polar aprotic solvent DMF. For these SN2 reaction, we need a good nucleophile. Compare with IN3, NaN3 is a good source for N3 (azide ion So for this conversion, the best reagent is NaN3 and DMF Option A is the right answer.