In this homework I was surprised especially by the answer for B, and slightly unsure about D, although I was leaning toward Sn2. For both of these questions, E2/E1 was not considered as a possibility. We are only supposed to consider substitution, although any thoughts about elimination are welcome.
I attached pictures of both of them.
B is a primary halide with acetate as a nucleophile and acetic acid as solvent. I was thinking it should be a slow Sn2, because the solvent is protic. Professor is saying Sn1. On a primary halide?? With no rearrangement??
And then for D, it is a secondary halide with cyanide as a nucleophile and methanol solvent. I was again thinking it should be a kind of slow Sn2, because the solvent should is protic. Professor is saying Sn1. The whole issue of Sn1 on secondary is controversial, and cyanide is a pretty good nucleophile. I don't remember seeing these exact conditions before in any textbook.
Anyone have any thoughts?