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 S 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

Part (a). Yes, the product is chiral.

Explanation: The name of the product is (1R,4s,7S)-4-azido-1,4,7-trimethyl-10-oxabicyclo[5.2.1]decane

Part (b).

(i) High strain present in the three-fold tertiary alkyl oxonium salt.

(ii) Unfavorability of the carbocation at the cyclic junction.

(iii) High stability of the product