Dehydrooligopeptides. II. The Synthesis of Dehydrodehydrodipeptides by Direct Coupling and Base-catalyzed β-Elimination
The direct coupling between N-protected α-dehydroamino acid (1) and N-free α-dehydroamino acid ester (2) by the acid-chloride method was carried out to give several dehydrodehydrodipeptides (7).Furthermore, the two kinds of dehydrodipeptides with a hydrox