A study of polychlorinated leucine derivatives: synthesis of (2S,4S)-5,5-dichloroleucine

The first total synthesis of (2S,4S)-5,5-dichloroleucine has been achieved in 11 steps from l-pyroglutamic acid. A key step is the dichlorination process on the hydrazone of aldehyde 13 with CuCl₂ in triethylamine.