Diastereoselective ring cleavage of azetidines with cyanogen bromide

Sustainable continuous flow synthesis of β-aminocarbonyls via acid-catalyzed hydration of N-Boc-2-azetines

“…24 Surprisingly, while the ring-opening of azetidine leading to α-aminoketones and diversely β-functionalized amines have been recently reported, the acid-promoted hydration of 2-azetines to the putative β-aminocarbonyls remains unexplored. 25,26…”

“…24 Surprisingly, while the ring-opening of azetidine leading to α-aminoketones and diversely β-functionalized amines have been recently reported, the acid-promoted hydration of 2-azetines to the putative β-aminocarbonyls remains unexplored. 25,26 The initial stages of this synthetic progress were marked by the unexpected discovery that NMR analysis of purified compound 2b using commercially available CDCl 3 yielded a changing ratio of 2b and 4b over time. However, employing CDCl 3 aged on K 2 CO 3 allowed for obtaining NMR spectra of pure 2b, indicating that the acidic content and residual water in commercial CDCl 3 likely influenced the results.…”

Switchable reactivity of 2-Azetines: Ionic versus radical pathway for accessing β-aminocarbonyls and 2,3-disubstituted azetidines

“…[11] Surprisingly, while ringopening transformation of azetidine leading to αaminoketones and diversely β-functionalized amines have been recently reported, the acid-promoted hydrolysis of 2-azetines to the putative βaminocarbonyls remains unexplored. [12,13] To fill this gap and gather some unambiguous mechanistic information, we first monitored by NMR the mild transformation of compound 2a with the residual water content and traces of HCl in commercial CDCl3 (Scheme 2). With our delight, we observed the quantitative formation of aminoaldehyde 4a after 12h.…”