Heteropoly acids-catalyzed organic reactions in water: doubly green reactions

The organic reactions in water, as the most significant green solvent, have attracted much attention due to their unique properties over conventional organic ones. In the catalytic area, heteropoly acids (HPAs) are also promising green solid acids to replace environmentally harmful liquid acid catalysts. Herein, we wish to report the organic reactions catalyzed by HPAs, their salt, and polyoxometalates (POMs) in aqueous systems.     

Amine synthesis via carbonylation reactions: aminomethylation

The preparation of aliphatic amines and alicyclic diamines by reaction of olefins, synthesis gas and dimethylamine, known as aminomethylation, was investigated. Synthesis involves homogeneous rhodium and ruthenium catalysts or mixtures thereof at very low concentrations. Employing 3–12 ppm Rh and 50–100 ppm Ru results in up to 97% selectivity towards the amines at conversions of up to 98% if aliphatic mono-olefins are used as starting materials. At high catalyst concentrations (173 ppm Rh, 2660 ppm Ru) the corresponding diamine is obtained from dicyclopentadiene in 89% yield. The influence of reaction parameters and catalyst ratios on the n/i-selectivity of the product indicates the scope as well as the limits of such a multi-step synthesis for a commercial process.     

Recent development of vinylogous Mukaiyama aldol reactions

The vinylogous Mukaiyama aldol reaction (VMAR) is a powerful tool of polyketide synthesis, which constructs a large size structure by simultaneous introduction of the stereogenic center(s) and the α,β-unsaturated carbonyl group. A variety of stereocontrolled VMARs have been developed and applied to natural product synthesis. This review is focused on recent development of the vinylogous Mukaiyama aldol reaction using s-trans silyl dienolates.     

Lewis acid-nitromethane complex-promoted Friedel-Crafts reactions of PS-DVB-resins

Aminomethyl-polystyrene resins were prepared using FeCl₃-nitromethane and FeCl₃-benzophenone complexes as Friedel-Crafts catalysts. All the resins were highly loaded and functionalized with Rink amide linker. A comparative synthesis of the classic difficult sequence ACP (65-74) on the prepared resins by Fmoc/t-Bu chemistry is presented. The target peptide of highest purity (91%) was that prepared using FeCl₃-nitromethane.     

Amino acid catalyzed thio-Michael addition reactions

Using amino acid as a catalyst, an inexpensive, nontoxic, environmentally friendly, metal-free reaction procedure for C-S bond formation via thio-Michael addition reaction has been developed. The thio-Michael addition products were obtained in excellent yields under mild and neutral conditions. This metal-free catalytic protocol was found to be a good alternative to the existing metal catalyst methodology for the thio-Michael addition reaction.     

抗体酶催化的不对称反应

本文综述了抗体酶催化的不对称反应, 并讨论了抗体酶的应用前景。     

Structure-inheriting solid-state reactions under hydrothermal conditions

We have explored several structure-inheriting solid-state reactions (SISSRs) under hydrothermal conditions for syntheses in the Co-Mo-O system. And we found an interesting hydrothermal SISSR from CoMoO₄·3/4H₂O to high-pressure (hp-) phase of CoMoO₄, which enabled us to considerably reduce the severe conditions for the synthesis of hp-CoMoO₄. As similar hydrothermal SISSRs are expected to be useful tools for material syntheses, we also briefly discuss them as a means of developing novel material syntheses and designs.     

Synthesis of some new germasesquioxides by intramolecular catalytic Mannich-type reactions

A convenient procedure for the preparation of some new germasesquioxides containing phosphonyl groups carried by an intramolecular catalytic Mannich-type reaction is reported.     

Cascade reactions in total synthesis

The design and implementation of cascade reactions is a challenging facet of organic chemistry, yet one that can impart striking novelty, elegance, and efficiency to synthetic strategies. The application of cascade reactions to natural products synthesis represents a particularly demanding task, but the results can be both stunning and instructive. This Review highlights selected examples of cascade reactions in total synthesis, with particular emphasis on recent applications therein. The examples discussed herein illustrate the power of these processes in the construction of complex molecules and underscore their future potential in chemical synthesis.     

Metathesis reactions in total synthesis

With the exception of palladium-catalyzed cross-couplings, no other group of reactions has had such a profound impact on the formation of carbon-carbon bonds and the art of total synthesis in the last quarter of a century than the metathesis reactions of olefins, enynes, and alkynes. Herein, we highlight a number of selected examples of total syntheses in which such processes played a crucial role and which imparted to these endeavors certain elements of novelty, elegance, and efficiency. Judging from their short but impressive history, the influence of these reactions in chemical synthesis is destined to increase.     

金属有机化合物催化的环化反应新进展

综述了近年来金属有机化合物催化的环化反应在合成碳20环及杂环化合物中的应用。     

Structural modification of unsymmetrically substituted monophthalocyanines by nucleophilic reactions

New 2-nitro-substituted phthalocyanine zinc complexes were synthesized. The nucleophilic substitution of the NO₂ group was used for the first time for the structural modification of unsymmetrically substituted monophthalocyanines. The electronic absorption spectra of phthalocyanines were studied. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2036–2040, September, 2005.