Highly Facialselective Synthesis of Pyranose 1,3-Oxazines and Their Ring Opening with Nucleophiles: A Novel Entry to 2-<i>C</i>-Branched Glycosides
作者:Biao-Lin Yin、Ze-Ren Zhang、Li-Wen Xu、Huanfeng Jiang
DOI:10.1021/ol2019604
日期:2011.10.7
A TMSOTf-promoted cycloaddition of N-benzoyl-N,O-acetals with various glycals and 3-deoxy glycals affords pyranose 1,3-oxazines with high facial selectivity. In addition, a highly diastereoselective ring opening of the resulting pyranose 1,3-oxazines is reported. With diverse nucleophiles, these reactions take place upon heating at 80 degrees C. This novel ring-opening reaction affords structurally diversified 2-C-branched glycosides with three newly formed contiguous stereocenters.