Studies directed towards the synthesis of botcinolides: synthesis of the nonalactone ring of 2-epibotcinolide

Synthesis of the polyoxygenated nonalactone ring of 2-epibotcinolide was achieved using a highly stereoselective aldol reaction of the titanium enolate from a lactate-derived chiral ketone, a stereoselective dihydroxylation and a Yamaguchi macrolactonization reaction.     

A double Mannich approach to the synthesis of substituted piperidones—application to the synthesis of substituted E-ring analogues of methyllycaconitine

The double Mannich reaction of acyclic α,γ-substituted β-keto esters and bis(aminol) ethers gives substituted 3,5-substituted-4-piperidones with high levels of diastereoselectivity. These piperdiones can be easily transformed into substituted E-ring analogues of the delphinium alkaloid methyllycacotine.     

Towards synthesis of kavalactone derivatives

Kavalactone derivatives were synthesized using a Heck reaction of the 4-methoxy-6-vinyl-5,6-dihydropyran-2-one with aryl iodides. The Suzuki-Miyaura reaction of an aryl boronic acid and (Z)-4-methoxy-6-(2-iodovinyl)-5,6-dihydropyran-2-one has also been successfully used to produce both Z and E isomers of lactones.     

Studies toward the synthesis of dienophile unit of methyl sarto-tuoate

The preparation of C3-C14 fragment of the dienophile unit of methyl sartotuoate is described.The key steps included Roush reaction and CuI catalyzed epoxy-opening reaction of i-PrMg-Br.     

Tandem Hass-Bender/Henry reaction for the synthesis of dimethylnitro alcohols from benzylic halides

Dimethylnitro alcohols are constructed in a one-pot process from benzylic halides and 2-nitropropane. The use of tetrabutylammonium fluoride (TBAF) as the promoter is essential for this tandem Hass-Bender/Henry reaction to proceed.     

One-pot three-component synthesis of the spiroacenaphthylene derivatives

A facile and efficient one-pot three-component synthesis of the spiroacenaphthylene derivatives was achieved, via the reaction of acenaphthequinone, malononitrile/ethylcyanoacetate and various reagents including α-methylencarbonyl compounds/enols.     

白花丹酸的简易合成法

设计了以邻苯二酚为起始原料的新合成路线, 在不同保护基的条件下用二条合成路线合成了白花丹酸, 方法的特点是以杂原子诱导的芳基锂化反应实现了区域专一性芳酰化; 用KH为碱顺利实现了羰基α位的羧甲基化; 采用环己酮保护酚羟基后, 后处理方便, 收率提高。     

An enantioselective organocatalyzed aza-MBH domino process: application to the facile synthesis of tetrahydropyridines

A chiral acid-base organocatalyst was found to promote an aza-MBH domino process between α,β-unsaturated carbonyl compounds and N-tosylimines to afford tetrahydropyridine derivatives with high enantioselectivity.     

Convenient stereoselective synthesis of some 3-aminosteroid scaffolds

Abstract

An efficient stereoselective synthesis 3α- and 3β-aminoandrostan-17-one and 3α-amino dehydroepiandrosten-17-one based on a Mitsunobu reaction has been developed, using azide as the ammonia equivalent. All the products were isolated in high yield.     

改进的Ugi法合成胺烷基二茂铁衍生物的反应研究

在改进的Ugi法会成胺烷基二茂铁衍生物的反应中，研究了反应的投料比、反应底物、反应温域等因素对反应的影响，并对反应机理进行了探讨。     

Enantioselective synthesis of oseltamivir phosphate

The key steps in the enantioselective synthesis of Tamiflu include an asymmetric Diels-Alder reaction, Mitsunobu inversion using Fukuyama modified Weinreb reagent, carbamate directed epoxidation. Epoxide opening with trimethylsilyl azide furnished a 3:1 mixture of regioisomers that converged to afford the same aziridine. Attempted preparation of the unsaturated ester regioselectively using 2-iodoxybenzoic acid (IBX) following Nicolaou’s protocol failed. The unsaturated ester was prepared by phenylselenylation followed by selenoxide elimination.     

Studies directed toward the synthesis of the massileunicellins

An approach to the massileunicellins is described that employs a cycloaldol reaction to assemble the isobenzofuran bicyclic core. A stereoselective rearrangement-epoxidation-oxidation cascade and a chelation controlled addition to a hindered acyl furan are used to install the C3, C11, C12, and C13 oxygens. The synthesis establishes eight of the nine stereocenters present in the isobenzofuran core of the massileunicellins.     

Intercepted-Knoevenagel condensation for the synthesis of unsymmetrical fused-tricyclic 4H-pyrans

4H-Pyrans (4H-Pys) and 1,4-dihydropyridines (1,4-DHPs) are important classes of heterocyclic scaffolds in medicinal chemistry. Herein, an indium(III)-catalyzed one-pot domino reaction for the synthesis of highly functionalized 4H-Pys, and a model of 1,4-DHP is reported. This alternative approach to the challenging Hantzsch 4-component reaction enables the synthesis of fused-tricyclic heterocycles, and the mechanistic studies underline the importance of an intercepted-Knoevenagel adduct to achieve higher chemoselectivity towards these types of unsymmetrical heterocycles.     

Three-component indole synthesis using ortho-dihaloarenes

A three-component synthesis of substituted indoles is accomplished starting from ortho-dihaloarenes through the use of a multicatalytic system consisting of an N-heterocyclic carbene palladium complex and CuI. The corresponding indole derivatives are obtained as single regioisomers in high yields of isolated product.     

Total synthesis of the proposed structure of iriomoteolide-1a

Full details of the total synthesis of the proposed structure of iriomoteolide-1a (1) are described. The key steps include (i) a Sakurai reaction between allylsilane 11 and aldehyde 10 that bears both a tertiary chiral center and vinyl iodide moiety (ii) an anti-aldol reaction to construct the C18/C19 chiral centers (iii) a B-alkyl Suzuki-Miyaura coupling reaction to assemble the C7-C23 fragment, and (iv) a macrocyclic ring-closing metathesis to complete the construction of the target molecule. Two different approaches to access penultimate precursor 2 are delineated. The NMR spectra of the synthetic iriomoteolide-1a (1) were found not to match those reported for the natural product bringing into question its true structural identity.     

Design and synthesis of self-healing polymers

Self-healing polymers represent a class of materials with built-in capability of rehabilitating damages. The topic has attracted increasingly more attention in the past few years. The on-going research activities clearly indicate that self-healing polymeric materials turn out to be a typical multi-disciplinary area concerning polymer chemistry, organic synthesis, polymer physics, theoretical and experimental mechanics, processing, composites manufacturing, interfacial engineering, etc. The present article briefly reviews the achievements of the groups worldwide, and particularly the work carried out in our own laboratory towards strength recovery for structural applications. To ensure sufficient coverage, thermoplastics and thermosetting polymers, extrinsic and intrinsic self-healing, autonomic and non-autonomic healing approaches are included. Innovative routes that correlate materials chemistry to full capacity restoration are discussed for further development from bioinspired toward biomimetic repair.     

Iodine-promoted three-component reaction for the synthesis of spirooxindoles

An iodine-promoted three-component reaction for the construction of spirooxindoles has been developed through the green reaction system of catalytic amount of molecular iodine as an alternative catalyst for Lewis acids. Various substituted isatins were able to react with different cyclic 1,3-dicarbonyls and 4-hydroxyl coumarins through this reaction strategy, which shows good functional group tolerance and efficiency.     

An annulation method for the synthesis of alkyl-substituted 6-carbomethoxy-2-pyridones

A protocol for the synthesis of 5-alkyl and 3,5-dialkyl-6-carbomethoxy-2-pyridones was devised. Key steps include a Mannich reaction, acylation of a tosylamine, and a PPh₃/TiCl₄-promoted intramolecular Reformatsky-type reaction with a thioester as the electrophile. The latter process typically afforded a vinylogous thiocarbamate via elimination of water rather than the Dieckmann-type product which would have resulted from elimination of the thiol. However, the Dieckmann-type ketone product was obtained in one instance. Subsequent elimination of the tosyl group and desulfurization completed the pyridone synthesis.