9. Design, construction and properties of peptide N-terminal cap templates devised to initiate α-helices. Part 3.? Caps derived from N-[(2S?)-2-chloropropionyl]-(2S?)-Pro-(2R)-Ala-(2S,4S?)-4-thioPro-OMe Arwel Lewis,Trevor J. Rutherford,John Wilkie,Thierry Jenn,David Gani J. Chem. Soc. Perkin Trans. 1 1998 3795