Synthesis of conformationally constrained hydroxy-α-amino acids by intramolecular conjugate addition

Summary.

An efficient and easily applicable method for the synthesis of a variety of hydroxy-α-amino acids analogues of serine and phenylalanine has been established. The method involves the stereoselective intramolecular conjugate addition of the benzamide group to cyclohexenone promoted by Lewis acid. Subsequent transformations of functional groups pro-vide the conformationally constrained 2-hydroxy- and 2,4-dihydroxy-6-phenylcyclohexane-α-amino acids.