281681-22-9Relevant academic research and scientific papers
Synthesis, structure and comparative stability of β-hydrazono, oximino methyl ether and imino boronates
Mears, Richard J.,Sailes, Heien E.,Watts, John P.,Whiting, Andrew
, p. 3250 - 3263 (2000)
β-Hydrazono and oximino ether boronates have been prepared by the sequential lithiation of the corresponding methyl hydrazone or oxirhe methyl ether, followed by reaction with an iodomethylboronate ester, typically in the form of the pinacol ester. The resulting products have contrasting hydrolytic stabilities. β-Hydrazono boronates are highly sensitive to intramolecularly catalysed hydrolysis, providing the corresponding β-keto boronates in generally high yields; β-oximino ether boronates are stable to silica gel chromatography and show evidence of E-Z-isomerisation. Stable homochiral boronate ester derivatives of β-oximino ethers can be readily prepared by a double transesterification process, via a diethanolamine-mediated pinacol ester exchange, followed by diethanolamine ester hydrolysis-reesterification process with a homochiral diol. β-Imino boronates can be generated in situ by condensation of the corresponding β-keto boronate with a primary amine, however the resulting imine function is highly hydrolytically unstable and cannot be isolated in a pure form. The Royal Society of Chemistry 2000.
Synthesis, structure and comparative stability of β-hydrazono, oximino methyl ether and imino boronates
Mears, Richard J.,Sailes, Helen E.,Watts, John P.,Whiting, Andrew
, p. 3250 - 3263 (2008/10/08)
β-Hydrazono and oximino ether boronates have been prepared by the sequential lithiation of the corresponding methyl hydrazone or oxime methyl ether, followed by reaction with an iodomethylboronate ester, typically in the form of the pinacol ester. The resulting products have contrasting hydrolytic stabilities. β-Hydrazono boronates are highly sensitive to intramolecularly catalysed hydrolysis, providing the corresponding β-keto boronates in generally high yields; β-oximino ether boronates are stable to silica gel chromatography and show evidence of E-Z-isomerisation. Stable homochiral boronate ester derivatives of β-oximino ethers can be readily prepared by a double transesterification process, via a diethanolamine-mediated pinacol ester exchange, followed by diethanolamine ester hydrolysis-reesterification process with a homochiral diol. β-Imino boronates can be generated in situ by condensation of the corresponding β-keto boronate with a primary amine, however the resulting imine function is highly hydrolytically unstable and cannot be isolated in a pure form.
'Transmitted' remote double diastereoselection effects on the asymmetric reduction of β-boronate oxime ethers
Sailes, Helen E.,Watts, John P.,Whiting, Andrew
, p. 2457 - 2461 (2007/10/03)
Remote asymmetric induction in the reduction of a homochiral β-boronate oxime ether to the corresponding amine failed to provide asymmetric induction with a chiral reducing agents, but use of a chiral reducing agent produced extreme double diastereoselection effects which show that remote asymmetry can be 'transmitted' by suitable choice of a 'partner' molecule. (C) 2000 Published by Elsevier Science Ltd.
