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Conventional self-healing is about the recovery of shape and mechanical properties. In contrast, recovery of functional properties is still a great challenge, especially for optical functional materials, as the known self-healing methods are incompatible with optical properties. By utilizing the synergistic effect between Au nanorods and vitrimer, the alignment of Au nanorods can be achieved in the crosslinked polymer. The optical properties of the resulting polarizing film, such as light transmittance and polarization degree, can be fully recovered without an external repair agent. With simple laser irradiation to induce the photothermal effect of Au nanorods, the shape-memory effect of vitrimer returns the Au nanorods to their initial orientation, and the plasticity achieves in situ self-healing of the cutting area. The self-healing of polarizing film provides a new research direction and reference for the application of self-healing systems in functional materials.

Efficient methods for the direct arylation and deacylative arylation of β-ketophosphonates with iodoarenes in presence of a copper(I) or a copper(II) salt as the catalysts were developed. The corresponding α-arylphosphonates were obtained in high yields. A tentative mechanism for the deacylative arylation reaction was proposed on the basis of the experimental data.

The cross aldol reaction between enolizable aldehydes and α-ketophosphonates was achieved for the first time by using 9-amino-9-deoxy-epi-quinine as the catalyst. β-Formyl-α-hydroxyphosphonates were obtained in high to excellent enantioselectivities. The reaction works especially well with acetaldehyde, which is a tough substrate for organocatalyzed cross aldol reactions. The products were demonstrated to have anticancer activities.

Aldol reaction is one of the most important carbon-carbon bond formation reactions1 and, therefore, many asymmetric variants of this reaction have been developed in the past.1 Since List and Barbas discovered the proline-catalyzed cross aldol reaction of ketones and aldehydes,2 many amine derivatives, mainly proline derivatives, have been developed for the asymmetric cross aldol reactions.3 Mechanistically, these catalysts activate the ketones or enolizable aldehydes through the formation of an enamine intermediate (Scheme 1, upper equation).3 The mechanism is usually a combination of both covalent and noncovalent catalyses since most of these catalysts also contain a hydrogen bonding moiety to direct the approach of the enamine acceptor. In contrast, although enol and enolate (Scheme 1, lower equation) are the active intermediates in the original aldol reactions,4 organocatalyzed enantioselective direct aldol reaction of unactivated ketones via the enolate mechanism is very difficult, because the acidity of the α-proton in these ketones is very low. To our knowledge, there has been no such report.5,6,7 Nevertheless, the enolate mechanism does have certain advantages, especially when the formation of an enamine is difficult. During our study of using activated ketone compounds as the enamine acceptors for the organocatalyzed aldol reactions,8 we envisioned such an organocatalyzed enolate-mediated aldol reaction should be possible if the enolate acceptor is sufficiently activated, because the equilibrium favors the formation of the product with such a substrate. Herein we wish to report the first enantioselective aldol reaction of unactivated ketones involving the enolate mechanism, which may be used for the high enantioselective synthesis of 3-alkyl-3-hydroxyindolin-2-ones.9

A new set of amino acid descriptors, SZOTT (Scores of Zero dimension, One dimension, Two dimension, Three dimension) was derived from principal component analysis on a matrix of 1369 descriptors including 0D, 1D, 2D and 3D information of 20 coded amino acids. SZOTT scales were then employed to represent structures of HLA-A*0201 restrictive CTL epitopes, and further, quantitative sequence-activity modelings (QSAMs) were constructed based on partial least squares and back-propagation artificial neural networks. Satisfying results show that structural information related to biological activities of HLA-A*0201 restrictive CTL epitopes can be preferably represented by SZOTT scales, which may be a useful structural representation technique for study of QSAMs of peptides.

The isolation and the structure elucidation of crotonlaevin A (Ia), B (Ib), C (II), D (IIIa), E (IIIb), F (IIIc), G (IV), H (Va), I (Vb), J (VIIa), K (VIIb), L (VIIc), M (VIII), N (IX), O (Xa), and P (Xb) as well as the additional new natural product (VI) is described.

The reaction of the tetravalent uranium [U(IV)] with dimethyldioxirane (DMD) in strongly acidic water–acetone solutions is accompanied by chemiluminescence (CL) in the visible (Vis) and infra-red (IR) regions. At least three independent reaction pathways are involved in the U(IV)–DMD oxidation: the first entails the non-chemiluminescent oxidation of U(IV) to the uranyl ion (UO22+); the second involves the catalytic decomposition of DMD by U(IV) to afford singlet oxygen, as manifested by its characteristic IR-CL; and in the third process, slow Vis-CL (510–540 nm) is emitted, following DMD consumption. Copyright © 2002 John Wiley & Sons, Ltd.

Direct arylation of β-ketophosphonates (I) and (V) with aryl iodides proceeds smoothly in the presence of Cu(I)—proline catalyst to afford α-aryl-β-ketophosphonates (IV) and (VI), resp., in high yields.

Cross aldol reaction between 4,5-dioxopyrroles (I) and ketones (II) and (IV) in the presence of chiral catalysts is investigated.

Condensation of cyclic 1,3-diones with alkylidene cyanoacetates in the presence of the quinine-based thiourea renders possible the preparation of various biologically interesting benzopyran structures.

It is demonstrated that novel Zn(II) and Cd(II) metal-organic framework materials (I) can be used with similar efficiency in the title reaction.

Cinchonidine thiourea CIN is found to be superior to other catalysts (9 examples) in terms of both diastereoselectivity and enantioselectivity obtained for product (IIIa).

The quinidine-thiourea-catalyzed asymmetric Michael addition of diphenylphosphite towards β-nitroolefins is significantly improved by filtration of diphenylphosphite through molecular sieves and addition of molecular sieves to the reaction mixture.

Aldol reaction is one of the most important methods for the formation of carbon-carbon bonds. Because of its significance and usefulness, asymmetric versions of this reaction have been realized with different approaches in the past. Over the last decade, the area of organocatalysis has made significant progresses. As one of most studied reactions in organocatalyses, organocatalyzed aldol reaction has emerged as a powerful tool for the synthesis of a large number of useful products in optically enriched forms. In this review, we summarize our efforts on the development of novel organocatalyzed aldol reactions for the enantioselective synthesis of biological active molecules. Literatures closely related to our studies are also covered.

An equimolar mixture of quinidine-derived thiourea and L-proline is highly efficient to promote the asymmetric cyclocondensation of dinitriles with pyrazolone (II) to give the title compounds with low to moderate e.e.

The asymmetric aldol reaction of unactivated ketones and activated carbonyl compounds is realized with a quinidine-derived thiourea catalyst, and involves an enolate mechanism instead of the widely used enamine mechanism.

Biginelli reaction of acetoacetate (I) with urea (II) and aromatic or aliphatic aldehydes proceeds smoothly in the presence of a quinidine-derived primary amine (QDA) as organocatalyst to give the title dihydropyrimidinones (IV) and (VI), resp., in up to 78% optical purity.

Cyclopropylphosphine oxides react with the salts of N-alkylamides, N-arylamides and phthalimide to produce dihydropyrrole derivatives in moderate to good yields.

2-Amino-8-oxo-tetrahydro-4H-chromene-3-carbonitriles were synthesized for the first time from a tandem Michael addition - cyclization reaction between cyclohexane-1,2-dione and benzylidenemalononitriles. An enantioselective synthesis of these compounds was achieved in moderate ee values (up to 63% ee) by using a cinchona alkaloid-derived thiouea catalyst.

The new optically active C 2 -symmetric ketones 3a (from mannitol) and 3b (from TADDOL) were prepared and the in - situ -generated dioxiranes (with Caroate TM as peroxide source) were shown to serve as effective oxidants for the asymmetric epoxidation (ee values up to 81%) of prochiral trans and trisubstituted olefins.

The dimethyldioxirane (DMD) oxidation of σH adducts derived from nitroarenes and the carbanion of 2-phenylpropionitrile yields unexpectedly the phenols 5 as the major products, while the usually observed nitroarenes 4 are formed in very little amounts, if any. The phenol yield was much improved when a small quantity (0.5−1.0 equiv.) of water was added at the start of the reaction. This novel oxidation of Meisenheimer complexes provides the first direct synthesis of phenols from nitroarenes, an unprecendented transformation.

The reaction of nitrobenzylic carbanions with dimethyldioxirane (DMD) results in oxidation at the carbanion center or at the nitronate center to give nitrobenzylic carbinols or quinomethanes, respectively. Minor amounts of the methylation products are also formed. Both of these processes were observed for carbanions of (p-nitroaryl)diarylmethanes. The outcome of the oxidation process is very sensitive to the reaction conditions.

β-(3-Hydroxypyrazol-1-yl) ketones have been prepared in high yields and excellent enantioselectivities (94−98% ee) via a Michael addition reaction between 2-pyrazolin-5-ones and aliphatic acyclic α,β-unsaturated ketones using 9-epi-9-amino-9-deoxyquinine as the catalyst. These results account for the first example of an aza-Michael addition of the ambident 2-pyrazolin-5-one anion to a Michael acceptor.

The first enantioselective synthesis of biologically active 6-amino-5-cyanodihydropyrano[2,3-c]pyrazoles has been achieved through a cinchona alkaloid-catalyzed tandem Michael addition and Thorpe-Ziegler type reaction between 2-pyrazolin-5-ones and benzylidenemalononitriles. The reaction may also be carried out in a three-component or a four-component fashion via the in situ formation of these two components from simple and readily available starting materials. The desired products were obtained in excellent yields with mediocre to excellent enantioselectivities (up to >99% ee).

Epoxidations, heteroatom oxidations, and Y-H insertions constitute the best investigated oxidations by dioxiranes. This article concerns epoxidation of the double bonds in the cumulenes, such as allenes, acetylenes, and arenes; the oxidation of heteroatom functionalities, mainly lone pairs on sulfur, on nitrogen, and on oxygen as the deoxygenation of N-oxides; the oxidation of C = Y functionalities, Y-H insertions such as in C-H alkanes, and Si-H silanes; and the oxidation of organometallic substrates including metal and ligand-sphere oxidation. Keywords: Dioxirane oxidations; Allenes; Alkynes; Arenes; Heteroatom substrates; Alkanes; Silanes; Organometallic compounds; Mechanisms; Nitrogen; Sulfur; Selenium; Phosphorus; Oxygen; Halogens; Method comparisons; Experimental procedures

Enantioenriched tetrasubstituted thiochromanes have been synthesized using a tandem Michael addition-Knoevenagel reaction between 2-mercaptobenzaldehydes and benzylidenemalonates with a 9-epi-aminoquinine thiourea derivative as the catalyst. Steric and electron effects were found to affect profoundly the enantioselectivity and diastereoselectivity of the reaction.

[reaction: see text] The first organocatalytic highly enantioselective nitroaldol reaction of alpha-ketophosphonates and nitromethane has been realized by using cupreine (2) or 9-O-benzylcupreine (3) as the catalyst. Both catalysts are highly reactive and highly enantioselective. alpha-Hydroxy-beta-nitrophosphonates have been synthesized in good yields and excellent enantioselectivities (or=90% ee) at a low catalyst loading (5 mol %). These nitroaldol products may be reduced to the biologically significant beta-amino-alpha-hydroxyphosphonates with complete retention of the stereochemistry.

N-PMP protected α-aminopropargylphosphonates have been synthesized by using a silver(I) triflate-catalyzed one-pot three-component reaction of terminal alkynes, p-anisidine, and diethyl formylphosphonate hydrate. Good to excellent yields of the desired products may be obtained with a very simple procedure.

Cyclohexylidenebishydroperoxide was successfully used as the oxygen source for the oxidation of α,β-unsaturated ketones for the first time. The corresponding epoxides were obtained in excellent yields under the Weitz–Scheffer reaction conditions.

[reaction: see text] The first organocatalytic cross aldol reaction of ketones and diethyl formylphosphonate hydrate has been realized by using readily available l-prolinamide as the catalyst. Secondary alpha-hydroxyphosphonates have been synthesized in high enantioselective (up to >99% ee) and good diastereoselectivity.

β-Alkoxy ketones were prepared by a one-pot three-component reaction of aliphatic aldehydes, ketones, and alcohols catalyzed by L-proline. Steric effects on the reaction were studied with substituted ketones, aldehydes, and alcohols, and the results indicate that reactions employing methyl ketones, α-unsubstituted aliphatic aldehydes and methanol produce the β-alkoxy ketones in the best yields when L-proline is used as the catalyst. The reaction mechanism is discussed.

1 Introduction 2 Chemical Reactivity 3 Conclusions 4 Acknowledgments Keywords: contemporary dioxirane chemistry; microwave-structural and NMR-spectral data of dioxiranes; complex chemical transformation; dioxiranes - structural and electronic characteristics; chemical reactivity; dioxirane mediated oxidation reactivity and selectivity; prochiral alkene dioxirane epoxidation; three-membered-ring cyclic peroxides - popular oxidants