BRANCHED BUILDING UNITS FOR SYNTHESIZING CYCLIC PEPTIDES

The present invention relates to building units suitable for the synthesis of backbone cyclized peptides. The building units of this invention have structures of Formula (I):wherein AAm and AAp are residues of natural or synthetic amino acids and U is CalphaON[(CH2)n+1W] or (CalphaH2N)[CO(CH2)qW], in which Calpha is a carbon atom and is the alpha carbon of AAm if m>0. W is NH-X or COY, and X is H, Boc, Z, Fmoc, or Alloc while Y is the hydroxyl group of a carboxylic acid moiety or a carboxylic acid protecting group. The letter m refers to an integer from 0 to 10; n is a number from 0 to 6; p is a number from 1 to 10; and q is a number from 1 to 6. The present invention is also directed to methods of synthesizing building units of Formula (I) via different routes.