β²‐ and β³‐Peptides with Proteinaceous Side Chains: Synthesis and solution structures of constitutional isomers, a novel helical secondary structure and the influence of solvation and hydrophobic interactions on folding

Enantiomerically pure β‐amino‐acid derivatives with the side chains of Ala, Val, and Leu in the 2‐ or 3‐position (β 2 ‐ and β 3 ‐amino acids, resp.), as well as with substituents in both the 2‐ and 3‐positions (β 2,3 ‐amino acids, of like ‐configuration) have been prepared (compounds 8 – 17 ) and incorporated (by stepwise synthesis and fragment coupling, intermediates 24 – 34 ) into β‐hexa‐, β‐hepta‐, and β‐dodecapeptides ( 1 – 17 ). The new and...