β-Selective 2-Deoxy- and 2,6-Dideoxyglucosylations Catalyzed by Bis-Thioureas

We present methods for β-selective 2-deoxy- and 2,6-dideoxyglucosylations of natural products, carbohydrates, and amino acids using bis-thiourea hydrogen-bond-donor catalysts. Disarming ester protecting groups were necessary to counter the high reactivity of 2-deoxyglycosyl electrophiles toward non-stereospecific S_N1 pathways. Alcohol and phenol nucleophiles with both base- and acid-sensitive functionalities were compatible with the catalytic protocol, enabling access to a wide array of 2-deoxy-β-O-glucosides.