Ephedrines and their acyclic derivatives

Ephedra compounds are well known due to their biological activity. They have been widely used in asymmetric synthesis during the last decades. To our knowledge no review about acyclic ephedra derivative compounds has appeared in the literature. In this paper, the synthetic methodologies to access ephedrines and chiral compounds derived from them are summarized, including those by substitution of the hydroxy group by chlorine, sulfur, nitrogen or phosphorous containing groups. Ephedrines and some ephedra derivatives have displayed biological activity. Some of them have been used as asymmetric inductor ligands or catalysts in asymmetric synthesis. Clearly the ephedra derivatives are potential candidates to be used in both areas.