The Experts below are selected from a list of 74340 Experts worldwide ranked by ideXlab platform

Yuan Xu - One of the best experts on this subject based on the ideXlab platform.

Chao Zhang - One of the best experts on this subject based on the ideXlab platform.

Christian Wolf - One of the best experts on this subject based on the ideXlab platform.

  • metal free one pot oxidative amination of Aldehydes to amides
    Organic Letters, 2007
    Co-Authors: Kekeli Ekouekovi, Christian Wolf
    Abstract:

    Metal-free oxidative amination of aromatic Aldehydes in the presence of TBHP provides convenient access to amides in 85−99% under mild reaction conditions within 5 h. This method avoids free carboxylic acid intermediates and integrates Aldehyde oxidation and amide bond formation, which are usually accomplished separately, into a single operation. Proline-derived amides can be prepared in excellent yields without noticeable racemization.

Michael North - One of the best experts on this subject based on the ideXlab platform.

  • a bimetallic aluminium salen complex for asymmetric cyanohydrin synthesis
    Tetrahedron Letters, 2009
    Co-Authors: Michael North, Courtney Williamson
    Abstract:

    Abstract In the presence of a phosphine oxide cocatalyst, a bimetallic aluminium(salen) complex was found to catalyse the asymmetric addition of trimethylsilyl cyanide to Aldehydes. Under optimised conditions, enantioselectivities of 53–96% were obtained using 2 mol % of the catalyst. An analysis of the reaction kinetics showed that the reactions exhibited first-order kinetics, with the rate of reaction being independent of the Aldehyde concentration.

  • synthetic and mechanistic studies on asymmetric cyanohydrin synthesis using a titanium salen bimetallic catalyst
    Tetrahedron, 2004
    Co-Authors: Yuri N. Belokon, Lisa A Clutterbuck, John A Blacker, Paola Carta, Michael North
    Abstract:

    Abstract A bimetallic titanium(salen) complex 1 was found to catalyse the asymmetric addition of ethyl cyanoformate to Aldehydes. Best results were obtained using 5 mol% of the catalyst at −40 °C and under these conditions, both aromatic and aliphatic Aldehydes were converted into cyanohydrin carbonates with up to 99% enantiomeric excess. The same catalyst could also be used to catalyse the asymmetric addition of potassium cyanide to Aldehydes in the presence of propionic anhydride, leading to cyanohydrin esters. Mechanistic studies showed that the enantiomeric excess of the product increased during the early stages of this reaction. However, by adding a ‘sacrificial Aldehyde’ this effect could be eliminated. The structure of the catalyst in solution was investigated using variable concentration, variable temperature and variable solvent NMR studies. These experiments showed that the catalyst exists as a mixture of monometallic 4 and bimetallic 1 species, a result which is consistent with previous mechanistic studies on the asymmetric addition of trimethylsilyl cyanide to Aldehydes and ketones catalysed by the same catalyst. A mechanistic rationale for all of these observations is reported.

Kekeli Ekouekovi - One of the best experts on this subject based on the ideXlab platform.

  • metal free one pot oxidative amination of Aldehydes to amides
    Organic Letters, 2007
    Co-Authors: Kekeli Ekouekovi, Christian Wolf
    Abstract:

    Metal-free oxidative amination of aromatic Aldehydes in the presence of TBHP provides convenient access to amides in 85−99% under mild reaction conditions within 5 h. This method avoids free carboxylic acid intermediates and integrates Aldehyde oxidation and amide bond formation, which are usually accomplished separately, into a single operation. Proline-derived amides can be prepared in excellent yields without noticeable racemization.