Helix mimetics and composition and methods related thereto

A fused bicyclo compound having the structure:

• or pharmaceutically acceptable salt or stereoisomer thereof,
• wherein
• Y is SO2—, —SO— or —S—;
• A is —(CR4R4a)m—;
• B is —(CR5R5a)n—;
• m is 1;
• n is 1;
• R4 and R5 are, at each occurrence, the same or different and independently an amino acid side chain moiety or an amino acid side chain derivative;
• R4a and R5a are, at each occurrence, the same or different and independently hydrogen, hydroxy, —COOH, —CONH2, —R6, —OR6, —COOR6, —COR6 or —CONHR6;
• R6 is a lower alkyl optionally substituted with halogen or hydroxy;
• R2 is -Z-(amino acid side chain moiety) or -Z-(amino acid side chain derivative), where Z is a direct bond or —C(═O)—, —C(═O)O—, —C(═O)NH—, —C(═NH)—, —SO2— or —P(O)2,3—;
• and
• R1 is independently selected from a solid support, an amino acid side chain moiety, an amino acid side chain derivative, a peptide, a peptide derivative, a protein, -Z-(amino acid side chain moiety) or -Z-(amino acid side chain derivative), wherein Z is a direct bond or —C(═O)—, —C(═O)O—, —C(═O)NH—, —C(═NH)—, —SO2— or —P(O)2,3—;
• wherein any two adjacent CH groups or adjacent NH and CH groups of the fused bicyclo compound optionally form a double bond;
• and with the provisos that:
• (a) when Y is —S— or —SO—, R1 is not hydrogen;
• and
• (b) when Y is —S— and m is 1, R4 and R4a are not both methyl when R1 is —C(═O)W, where W is phenyl, benzyl, —CH2O(phenyl) or —OC(═O)(benzyl).