Synthesis of Diverse C2‐Glyco‐Acyl Azides and ‐Ureas by Palladium‐Catalyzed Carbonylation Coupling of 2‐Iodoglycals
Antônio A. Soares-Paulino, Hélio A. Stefani
Abstract
Herein, we describe the synthesis of acyl azides and acyl urea glycals, a new class of C‐2 branched glycoconjugates, employing Pd‐catalyzed carbonylative coupling. A new strategy was developed to obtain acyl azides by carbonylative coupling between 2‐iodo‐glycals and NaN 3 catalyzed by Pd(dba) 2 /Xantphos and carbon monoxide as a carbonyl source. Acyl azide glycals were used as synthetic intermediates in obtaining new acyl urea glycals via carbonylative coupling catalyzed by Pd(OAc) 2 and 1,10‐Phen. Different glycal substrates, including disaccharide‐type, were studied, and various acyl azides and acyl ureas were prepared. Reaction yields were moderate to high (31–99 %) and reaction time varying from short to long (0.5–20 h).