Intercepted dehomologation of aldoses by N-heterocyclic carbene catalysis – a novel transformation in carbohydrate chemistry
作者:Markus Draskovits、Hubert Kalaus、Christian Stanetty、Marko D. Mihovilovic
DOI:10.1039/c9cc05906g
日期:——
The development of an N-heterocyclic carbene (NHC) catalysed intercepted dehomologation of aldoses is reported. The unique selectivity of NHCs for aldehydes is exploited in the complex context of reducing sugars. Examples of strong substrate governance for either intercepted dehomologation or a subsequent redox-lactonisation were identified and mechanistically understood. More importantly, it was shown
Palladium-Catalyzed C-Allylation of Benzoins and an NHC-Catalyzed Three Component Coupling Derived Thereof: Compatibility of NHC- and Pd-Catalysts
作者:Raphaël Lebeuf、Keiichi Hirano、Frank Glorius
DOI:10.1021/ol801644f
日期:2008.10.2
A large range of benzoins was successfully applied as C-nucleophiles in the palladium-catalyzed allylic alkylation with several allyl acetates, resulting in functionalized tertiary homoallylic alcohols. A number of unsymmetrical benzoins can be coupled with high levels of regio- and chemoselectivity. Finally, the challenging compatibility of free N-heterocyclic carbenes with a palladium catalyst has been utilized in a number of metal- and organocatalyzed three-component coupling reactions.