Recent Advances in the Reaction of MBH Carbonates: Scope and Mechanism

An efficient pyridine-catalyzed chemoselective fourcomponent cascade reaction of aromatic aldehydes, malononitrile/ cyanoacetates, Morita−Baylis−Hillman (MBH) carbonates, and alcohols has been established. This one-pot reaction progressed in an unusual reaction with solvent participation via a Knoevenagel condensation/oxa-Michael addition/S N 2′ substitution sequence. This method allowed for facile access to an array of functionalized chain alkylbenzenes and dihydroquinolinones bearing one allcarbon quaternary center in moderate to excellent yields. It is worth noting that the configuration of the all-carbon quaternary center could be modulated by changing only the electron-withdrawing groups via a tandem reduction/cyclization reaction.

Pyridine-Catalyzed Chemoselective Four-Component Cascade Reaction of Aromatic Aldehydes, Malononitrile/Cyanoacetates, MBH Carbonates, and Alcohols

Li,

Hu,

Yao

et al. 2024

Controllable Phosphine-Catalyzed Three-Component Domino Reaction of Activated Alkenes with Morita–Baylis–Hillman (MBH) Carbonates: Divergent Synthesis of Densely Functionalized Cyclopentanes and Diquinanes

Li,

Hu,

et al. 2024

An unexpected phosphine-catalyzed controllable three-component domino reaction involving [1 + 2 + 2] annulation and [1 + 2 + 2]/[3 + 2] sequential annulation reaction of 2-arylmethylidene cyanoacetates/malononitriles with Morita−Baylis− Hillman (MBH) carbonates has been developed. A broad range of densely functionalized cyclopentanes and diquinanes bearing five or four consecutive stereogenic centers, including two all-carbon quaternary stereocenters, were smoothly acquired in moderate to excellent yields under mild reaction conditions from readily available materials. Moreover, this divergent transformation enables the simultaneous generation of three or four new C−C bonds and one or two carbocyclic rings in only one step.C yclopentane derivatives are widely occurring subunits in pharmaceuticals and biologically active molecules among which densely functionalized cyclopentanes and diquinanes bearing multiple consecutive stereogenic centers are privileged structural motifs in natural products (Figure 1). 1 Selected examples are scandine, 1a canataxpropellane, 1b pactamycin, 1c paniculatine, 1d lycojaponicumin C, 1e calyciphylline N, 1f and anislactone A. 1g Such compounds have been demonstrated to be effective in treating rheumatic heart diseases, antibacterial/ anticancer activity, etc. 2 Therefore, these polysubstituted cyclopentanes and diquinanes have been a hot topic attracting significant attention from the organic synthetic community, and a large number of efficient synthetic methods for the rapid construction of the mentioned skeletons have been reported. 3 However, methods with a greater scope and practicality are still needed. To the best of our knowledge, phosphinecatalyzed annulation reactions have been well-established as powerful tools for the convenient creation of carbocycles and heterocycles. 4 In continuation of our interest in the field of organocatalysis, especially phosphine catalysis, 5 we sought to design a phosphine-catalyzed three-component domino

Visible-Light-Promoted Iron(II)/Lewis Base Catalysis for the Alkylation of Morita–Baylis–Hillman Acetates Using Carboxylic Acids

Golagani,

Prakash,

Thapa

et al. 2024

A novel photoinduced Fe(OTf)2/2,4,6-collidine-catalyzed alkylation of Morita–Baylis–Hillman (MBH) acetates using carboxylic acids in a regio- and stereoselective manner is reported. This method demonstrates a broad scope, encompassing various carboxylic acids and MBH acetates, including drugs and bioactive molecules, to synthesize densely functionalized cinnamates and acrylates. The reactions are performed in the green solvent dimethyl carbonate under oxidant-free conditions. Based on control experiments, a plausible mechanism involving an Fe(II)–Fe(III)–Fe(II) cycle is proposed.