The von Braun Reaction Applied to Azetidines

The von Braun reaction (the reaction of cyanogen bromide with tertiary amines) was applied to a series of functionalized N‐alkyl‐substituted azetidines. This reaction mainly led to the cleavage of the strained four‐membered ring to produce 3‐bromo N‐alkyl cyanamides in good yields with variable regioselectivity. The resulting cyanamide products were then employed as original building blocks for the synthesis of nitrogen heterocycles. The regio‐ and stereoselective ring cleavage of N‐alkyl azetidines by treatment with cyanogen bromide (i.e., the von Braun reaction) was studied in depth. The resulting 3‐bromo N‐alkyl cyanamides were then employed as original building blocks for the synthesis of nitrogen heterocycles.