Unsaturated O-glycosides

Hotha and Tripathi [45] reported a practical method based on microwave irradiation for Perrier reaction of per-O-acetylated glycals 49a,b with primary, secondary, allylic, benzylic, and monosaccharide alcohols they used a catalytic amount of niobium pentachloride to give the corresponding 2,3-unsaturated O-glycosides 51 and 53 with a stereoselectivity in high yields and with short reaction times (Scheme 12.24). 

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