Structure-Based Insight into the Asymmetric Bioreduction of the CC Double Bond of α,β-Unsaturated Nitroalkenes by Pentaerythritol Tetranitrate Reductase
作者:Helen S. Toogood、Anna Fryszkowska、Victoria Hare、Karl Fisher、Anna Roujeinikova、David Leys、John M. Gardiner、Gill M. Stephens、Nigel S. Scrutton
DOI:10.1002/adsc.200800561
日期:——
Biocatalytic reduction of alpha- or beta-alkyl-beta-arylnitroalkenes provides a convenient and efficient method to prepare chiral substituted nitroalkanes. Pentaerythritoltetranitratereductase (PETN reductase) from Enterobacter cloacae st. PB2 catalyses the reduction of nitroolefins such as 1-nitrocyclohexene (1) with steady state and rapid reaction kinetics comparable to other old yellow enzyme
Synthesis of substituted nitroolefins: a copper catalyzed nitrodecarboxylation of unsaturated carboxylic acids
作者:Balaji V. Rokade、Kandikere Ramaiah Prabhu
DOI:10.1039/c3ob41408f
日期:——
A novel, mild and convenient method for the nitrodecarboxylation of substituted cinnamic acid derivatives to their nitroolefins is achieved using a catalytic amount of CuCl (10 mol%) and tert-butyl nitrite (2 equiv.) as a nitrating agent in the presence of air. This reaction provides a useful method for the synthesis of β,β-disubstituted nitroolefin derivatives, which are generally difficult to access from other conventional methods. Additionally, this reaction is selective as the E-isomer of the acid derivatives furnishes the corresponding E-nitroolefins. One more salient feature of the method is, unlike other methods, no metal nitrates or HNO3 are employed for the transformation.
Building the buildingblocks: A highly enantioselective hydrogenation of β‐aryl‐β‐alkyl disubstituted nitroalkenes 1 has been developed. This method results in enantiomericallypure nitroalkanes 2, which are versatile precursors for chemical synthesis.
hydrazides depended to a great extent on the choice of a solvent and catalyst. In the presence of dimethylformamide (DMF), β-alkyl nitroalkenes more likely converted into electron-rich allyl nitro compounds, which reacted with sulfonyl hydrazides to afford allylsulfones with high regioselectivity. While in acetonitrile (CH3CN), vinyl sulfones were obtained directly via sulfonation of electron-deficient β-alkyl
protocol was developed for the preparation of allylic sulfones through direct condensation of sodium arylsulfinates and β,β-disubstituted nitroalkenes. The key step of this process was the Lewis base-promoted equilibrium between nitroalkenes and allylic nitro compounds. Through this process, the readily available conjugated nitroalkenes can be easily converted into allylic nitro compounds, which contain