Question

Molecule A (1,4,7-trimethyloxatriquinane) is a three-fold, tertiary alkyl oxonium salt. The compound is inert to solvolysis with alcohols, even at elevated temperatures, but it readily undergoes substitution with the strongly nucleophilic azide anion (N3) in chloroform (CHCl3, polar aprotic solvent). An SN 2 pathway is the only reasonable mechanistic interpretation for this reaction, despite the fact that substitution is occurring at a tertiary carbon center. (a) is the product chiral? (0.2 pts) (b) Describe three features of this reaction that make an SN2 pathway feasible. Note the 3-dimensional, ball- and-stick drawing of molecule A below. (0.3 pts) N3: chiral? (yes) (no) CHCI: molecule A

Answer 1

answer A)

In the above product the plane is drawn or which is pass through C-C and oxygen atom O and Methly wedge and and also N3- so that it cutting equal half towards us and half away from us

Note: N3 - is linear structure so equal cutting in between

Hence plane of symmetry present in the compound so it is not chiral.

b)Three features of reaction that favour S_N² that are

• First due to three methly substituted above the plane so nucleophile attack easily from back side give only one product. So one product is forming.
• Second the solvent is aprotic which favour S_N²  Thus CHCl₃ is enough polar to dissolve the reactant and nucleophile but not forming hydrogen bonding with the nucleophile, so nucleophile easily attack on reactant. Not feel any resist in path of atacking.
• Third  N3- is strong nucleophile , so strong nucleophile favour S_N² reaction