Reversal of Anomeric Selectivity with O-Glycosyl Trichloroacetimidates as Glycosyl Donors and Thiols as Acceptors Under Acid/Base Catalysis
作者:Amit Kumar、Richard R. Schmidt
DOI:10.1002/ejoc.201200138
日期:2012.5
Borontrifluoride or trimethylsilyl trifluoromethanesulfonate catalysed the generation of thioglycosides from O-glucopyranosyl or O-galactopyranosyl trichloroacetimidates and thiols giving mainly or exclusively α-thioglycosides. However, the same reactions with phenylboron difluoride as catalyst are highly β-selective. An SN2-type reaction course under acid/base catalysis is invoked by these and previous
Organoboron compounds. Part IX. Synthesis and properties of some 2-phenyl-1,3,2-oxazaborolans
作者:R. Harry Cragg、Alan F. Weston
DOI:10.1039/dt9750000093
日期:——
The synthesis and properties of some 2-phenyl-1,3,2-oxazaborolans are described and the i.r. spectra and general mass-spectral features of these compounds are discussed.
Thioboranes: their use in the synthesis of borazines
作者:R. H. Cragg、A. F. Weston
DOI:10.1039/c39720000079
日期:——
Borazines, of type (A), have been synthesised in high yields by the reaction of a tristhioborane with hydroxy- and mercapto-amines; the mass spectrum of the cysteamine compound shows an unusual fragmentation pattern.
Boron–sulphur compounds. Part VI. Organoboron compounds of cysteamine (2-aminoethanethiol)
作者:Richard H. Cragg、Alan F. Weston
DOI:10.1039/dt9730001054
日期:——
The synthesis and properties of a new class of compounds, based on the –B–S–CH2CH2–NH unit, are described. The reaction of trisalkylthioboranes and cysteamine gave a borazine which on reaction with ethylenediamine gave a novel unsymmetrical borazine. The mass spectral fragmentations of these compounds are fully discussed.
Thioboranes, of general formula PhnB(SR)3−n (where n = 0, 1, 2), have been obtained from the interaction of a lead thiolate and the corresponding chloroborane. The i.r. spectra, mass spectra and 11B NMR spectra of some of these compounds are discussed.
通式为Ph n B(SR)3- n(其中n = 0、1、2)的硫硼烷是从硫醇铅与相应的氯硼烷的相互作用中获得的。讨论了其中一些化合物的红外光谱,质谱和11 B NMR光谱。