Synthesis of Constrained Tetracyclic Peptides by Consecutive CEPS, CLIPS, and Oxime Ligation
                                
                                    
                                        作者:Dieuwertje E. Streefkerk、Marcel Schmidt、Johannes H. Ippel、Tilman M. Hackeng、Timo Nuijens、Peter Timmerman、Jan H. van Maarseveen                                    
                                    
                                        DOI:10.1021/acs.orglett.9b00378
                                    
                                    
                                        日期:2019.4.5
                                    
                                    In Nature, multicyclic peptides constitute a versatile molecule class with various biological functions. For their pharmaceutical exploitation, chemical methodologies that enable selective consecutive macrocyclizations are required. We disclose a combination of enzymatic macrocyclization, CLIPS alkylation, and oxime ligation to prepare tetracyclic peptides. Five new small molecular scaffolds and differently sized model peptides featuring noncanonical amino acids were synthesized. Enzymatic macrocyclization, followed by one-pot scaffold-assisted cyclizations, yielded 21 tetracyclic peptides in a facile and robust manner.