Surprisingly, amine 4 was stable in THF at room temperature and even under prolonged heating (entries 1-4). However, in the presence of LiCl (cat.), the isomerization into product 3a smoothly proceeded already at room temperature (entry 5). This experiment explained why we never observed "invisible" intermediate 4 in the reduction of nitrile 3 with LiAlH4 (Scheme 2): amine 4 formed in the first place and immediately isomerized into product 3a in the presence of Li + ions.