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One‐Pot Synthesis of N ‐Glycooxazolines, N ‐Glycoaminooxazolines, and N ‐Glycothiazolines from Glycals
Author(s) -
Reid Erica M.,
Vigneau Edward S.,
Gratia Synthia S.,
Marzabadi Cecilia H.,
De Castro Michael
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200130
Subject(s) - chemistry , glucal , amide , stereoselectivity , substituent , anhydrous , medicinal chemistry , organic chemistry , propionitrile , aryl , base (topology) , protecting group , catalysis , alkyl , acetonitrile , mathematical analysis , mathematics
Novel one‐pot syntheses of N ‐glycooxazolines (N at C‐1), N ‐glycoaminooxazolines, and N ‐glycothiazolines have been developed. Thus, the reaction of tri‐ O ‐benzyl‐ D ‐glucal or tri‐ O ‐benzyl‐ D ‐galactal with aryl amides, heteroaryl amides, thioamides, and substituted ureas in the presence of N ‐iodosuccinimide (NIS) in dry propionitrile at 45 °C afforded the cyclized products in good yields. When tris( O ‐ tert ‐butyldimethylsilyl)‐ D ‐glucal was employed, the 2‐deoxy‐2‐iodoglycosylamide was isolated instead. Treatment of this newly formed glycosylamide with an anhydrous base afforded the O ‐glycooxazoline (O at C‐1) in high to moderate yields. Product outcomes and the overall stereoselectivity of the reactions were found to be highly dependent on the nature of the sugar protecting group, the nature of the substituent on the amide, and the reaction temperature.