Amidoglycosylations of D-glucal 3-carbamates via Pd(II)-Pd(IV) catalysis

WCC 11

Lindsay M. Repka, lr2161@barnard.edu, Barnard College, 6329 Altschul, New York, NY 10027
We have studied amidoglycosylations of protected D-glucal 3-carbamates using palladium catalysts. Reactions from primary carbamates gave only minimal yield, and no reaction occurred without base. Amidoglycosylations of N-tosyl carbamates were attempted under seven sets of conditions, but no product formed, even at elevated temperatures and 30 mol % catalyst loading. The mechanism is expected to entail Pd(II)-Pd(IV) catalysis, based on research by Sanford, Sorensen, Stahl and Muņiz. Palladium-alkene coordination is followed by ring-forming nitrogen attack, deprotonation, oxidation of palladium, and intermolecular attack by acetate or an alcohol, regenerating Pd(II). Based on work of Muņiz, we are currently attempting diaminations from D-glucal urea derivatives. These reactions, expected to occur by Pd(II)-Pd(IV) catalysis, should involve coordination of palladium to one of the urea nitrogens, palladium-nitrogen addition across the alkene, and oxidation of palladium, followed by reductive elimination of palladium or by decomplexation, palladium elimination, and intramolecular attack by the anionic nitrogen.
 

The Merck Index Women in Chemistry
2:30 PM-4:30 PM, Monday, August 18, 2008 Pennsylvania Convention Center -- Hall C, Poster

Women Chemists Committee

The 236th ACS National Meeting, Philadelphia, PA, August 17-21, 2008