Preparation and Determination of X-Ray-Crystal and NMR-Solution Structures of γ2,3,4-Peptides.

(R,R,R)-γ-Amino acids with side chains in the 2-, 3-, and 4-positions, prepared by addition of acyloxazolidinones to a nitroolefin and hydrogenation, have been coupled to γ- tetra-, and γ-hexapeptides which are shown to form (M)-2.614 helices in the crystal state and in MeOH solution.