Synthesis of N-protected allylic amines from allyl ethers

A synthetic method for N-protected allylic amines from allyl ethers using chlorosulfonyl isocyanate (CSI) is presented. The reaction of 4-phenylbut-2-enyl methyl ether (1i) with CSI afforded methyl N-(1-benzylallyl)carbamate (2i) and methyl N-(4-phenylbut-2-enyl)carbamate (3i) in a 1:1.1 ratio. On the other hand, 1-benzylallyl methyl ether (1k) afforded the same products in a 4.6:1 ratio. The reactions of 1,4-diphenylbut-2-enyl methyl ether (1p) and (1-benzylcinnamyl) methyl ether (1q) with CSI gave only one product, methyl N-(1-benzylcinnamyl)carbamate (2p), due to the steric hindrance of the phenyl ring and the formation of a stable conjugated product. We also examined the reactions of diene ethers (4) with CSI.