Precise values of the 13C component vicinal coupling constants for calculating side-chain conformations in amino acids

From consideration of ¹H–¹H vicinal coupling constants and ¹³C? ¹H long-range coupling constants in a series of amino acid derivatives, the precise values of ¹³C component vicinal coupling constants have been calculated for the three minimum energy staggered rotamers for the C(α)H? C(β)H₂ side-chains of amino acids.