2. Essential Components: Earlier Developments 5449 2.1. Activated alkenes/alkynes 5450 2.1.1. Acyclic activated alkenes/ alkynes 5450 2.1.2. Cyclic activated alkenes 5451 2.2. Electrophiles 5451 2.3. Catalysts 5452 3. Essential Components: Recent Developments 5452 3.1. Activated Alkenes/Alkynes 5452 3.2. Electrophiles 5460 3.3. Catalysts 5477 4. Asymmetric Baylis-Hillman Reaction: Earlier Developments 5495

Recent contributions from the Baylis-Hillman reaction to organic chemistry.

Using soluble polymer supports to facilitate homogeneous catalysis.

A magnetic nanoparticle-supported quinuclidine was prepared and evaluated as a recoverable Morita-Baylis-Hillman catalyst. The supported catalyst 2 demonstrated comparable activity with that of DABCO and could be simply recycled with the assistance of an external magnet. The thus recycled catalyst could be reused for 7 times without significant loss of activity.

Magnetic Nanoparticle‐Supported Morita–Baylis–Hillman Catalysts

Dendrimers provide new and practical solutions to the complex problem of catalyst separation from the product stream. Dendrimers functionalized with active metal complexes are themselves soluble, nanosized catalysts that are capable of combining the high activity and selectivity of classical homogeneous catalysts with the enhanced separation capabilities added by the macromolecule. This report reviews the recovery and recycling of metallodendrimer catalysts by different separation techniques, such as nanofiltration, precipitation, or catalyst immobilization on solid supports, or by the use of appropriate solvent media, as illustrated by representative examples.

Dendrimers: Solutions For Catalyst Separation and Recycling–A Review† † Dedicated to the memory of Dr. José Antonio Delgado Oyagüe.

Scriven, Eric F. V., Toomey, Joseph E., Jr., and Murugan, Ramiah (Reilly Industries, Inc.). Commercial manufacture, industrial chemistry, and market uses of pyridine and pyridine compounds are reviewed. Pyridines often serve as intermediates for manufacture of products that are bioactive, such as medicinals, herbicides, insecticides, and fungicides. Significant end products for these market applications are identified. Important physical properties are also listed. Discussion of manufacture includes raw materials used, energy utilization, economics, toxicity of compounds, and safety factors. Vol. 20, pp. 641–679, 110 refs. to September 1994. 


Keywords:

Pyridine;
Pyridine bases;
Ring atoms;
Lutidine;
Formaldehyde;
Substituted pyridines;
Picolines;
Piperdines;
Derivatives;
Pharmacueticals;
Agorchemicals

Pyridine and Pyridine Derivatives

The Baylis–Hillman reaction of various aryl aldehydes with methyl vinyl ketone and acrylonitrile in the thermomorphic binary system (DMF/cyclohexane, 1/1, v/v) has been investigated. The phase selectively soluble alkyl-modified dendritic DMAP catalyst could be easily recycled via phase separation which was induced by cooling the temperature from 60 °C to room temperature. The corresponding Baylis–Hillman adducts were obtained in good yields and the recycled and reactivated dendritic catalyst almost gave the same results.

Phase selectively soluble dendritic derivative of 4-(n,n-dimethylamino)pyridine : an easily recyclable catalyst for Baylis-Hillman reactions

The application of non-imidazolium-based ionic liquid [EtPy][BF4] (N-1-ethylpyridinium tetrafluoraborate) as recyclable solvent for the Baylis–Hillman reactions was presented. Compared with the commonly used imidazolium-based ionic liquid [bmim][PF6] (1-n-butyl-3-methylimidazolium hexafluorophosphate) and [bdmim][PF6] (1-n-butyl-2,3-dimethylimidazolium hexafluorophosphate) that evidently reacts with aldehydes under basic conditions, ionic liquid [EtPy][BF4] is inert and the Baylis–Hillman reactions in [EtPy][BF4] proceed quickly with good yields.

Chang-qun Cai

Papers

Phase selectively soluble dendritic derivative of 4-(n,n-dimethylamino)pyridine : an easily recyclable catalyst for Baylis-Hillman reactions

Application of non-imidazolium-based ionic liquid in the Baylis-Hillman reactions : Rate and yield promoted