Polymer-Supported Synthesis of an Apratoxin Analogue

Significance

Polymer-supported synthesis of oxoapratoxin A (7), an oxazoline analogue of apratoxin A, was described. The report presents a ­versatile synthetic route for a facile synthesis of aparatoxin analogues for future SAR studies of the potent antitumor compounds. The linear elongation of 5 was achieved through three coupling-deprotection sequences with three Fmoc-protected amino acids. The 25-membered macrocyclization of 6 with HATU followed by removal of the TBS group with DAST afforded 7 in 58% yield.