Use of α‐Bromo Oxime Ethers in the Synthesis of 1,2‐Diamines

Oxime ethers 1 react with ammonia and primary amines to give α‐amino oxime ethers. The reaction of α‐bromo oxime ethers with sodium azide affords α‐azido oxime ethers. Hydrogenolysis of the azido compounds using 5% palladium on calcium carbonate as catalyst yields the α‐amino oxime ethers. The reaction of α‐azido oxime ethers with lithium aluminum hydride gives 1,2‐ethanediamine derivatives. The reaction of azido oxime ether 13 with LiAlH₄, and subsequently the reaction of the resulting mixture of the diamines 14 and 15 with phosgene, preferably gives cis‐4‐pentyl‐5‐methyl‐2‐imidazolidone (16) indicating that the reduction of 13 proceeds in a stereoselective manner to furnish mainly the syn‐1,2‐ethanediamine 15.