On the mechanism of the deoxygenation of secondary alcohols by the reduction of their methyl xanthates by tin hydrides
作者:Derek H.R. Barton、David Crich、Antonius Löbberding、Samir Z. Zard
DOI:10.1016/s0040-4020(01)90614-3
日期:1986.1
Two alternate proposals for the mechanism of reduction of xanthates by tributylstannane have been examined. Evidence has been secured that under normal reduction conditions the thiocarbonyl group is attacked reversibly. At a high enough temperature the carbon radical fragments to give eventually the reduction product. Under modified conditions, where no reducing agent (Sn-H) is present, the radical
Formation of silanethiols by reaction of silanes with carbonyl sulfide: implications for radical-chain reduction of thiocarbonyl compounds by silanes
作者:Yudong Cai、Brian P. Roberts
DOI:10.1016/s0040-4039(00)02109-2
日期:2001.1
tributyltin hydride in the Barton–McCombie deoxygenation of alcohols via their xanthates under mild conditions. Reduction of xanthates by silanes can produce COS as a by-product, leading to the in situ formation of silanethiol that will then act as a protic polarity-reversal catalyst for the reduction.
Bis(p-methoxyphenyl) telluroxide: a new, mild oxidising agent
作者:Derek H. R. Barton、Steven V. Ley、Clive A. Meerholz
DOI:10.1039/c39790000755
日期:——
Bis(p-methoxyphenyl) telluroxide is a mild and highly selective oxidising reagent for the conversion of thiocarbonyl groups into their oxo analogues and thiols into disulphides, and for the oxidation of a limited number of nitrogeneous compounds although many other easily oxidised functions are not affected.
13C NMR spectral assignment of five epimeric 3α-versus 3β-functionalized cholestane pairs
作者:S. S. Ramos、L. Santos、P. Almeida、W. B. Motherwell、M. C. Costa
DOI:10.1002/mrc.1635
日期:2005.10
NMR chemical shift assignments of five α‐ and β‐ epimeric pairs of cholestanes functionalized at C‐3 are presented. Empirical increment estimations proved to be a valuable tool for the unequivocal structural elucidation when compared with the chemical shift values of cholestanes derivatized by introduction of N‐ and S‐containinggroups at C‐3 in equatorial and axial positions. Moreover, the possibility