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O ‐(1‐Phenyl‐1 H ‐tetrazol‐5‐yl) Glycosides: Alternative synthesis and transformation into glycosyl fluorides
Author(s) -
Palme Monica,
Vasella Andrea
Publication year - 1995
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19950780418
Subject(s) - chemistry , glycosyl , fluoride , glycoside , pyridine , tetrazole , medicinal chemistry , stereochemistry , organic chemistry , inorganic chemistry
A number of new glycosyl donors, O ‐(1‐phenyl‐1 H ‐tetrazol‐5‐yl) glycosides, are prepared from the corresponding hemiacetals, commercially available 5‐chloro‐1‐phenyl‐1 H ‐tetrazole ( 2 ), and tetrabutylammonium fluoride (Bu 4 NF) in either THF or DMF. The mild reaction conditions are compatible with a variety of protecting groups. The glycosyl donors are treated with hydrogen fluoride‐pyridine complex (HF·py) to rapidly provide glycosyl fluorides in good‐to‐excellent yields, apparently by a (single or double) S N 2 mechanism as studied by both 1 H‐ and 19 F‐NMR spectroscopy. Under acidic conditions, glycosyl fluorides equilibrate partially or completely, equilibration requiring a large excess of HF · py.