基于天然氨基酸的双环手性季铵盐相转移催化剂的合成及催化性能研究

以L－脯氨酸及L－羟基脯氨酸为原料合成了4个新型手性季铵盐磁相转移催化 剂，并用于催化不对称查耳酮环氧化反应，高产率得到相应环氧化合物，ee最高达 9％。     

Anodic Amide Oxidation/Olefin Metathesis Strategies: Developing a Unified Approach to the Synthesis of Bicyclic Lactam Peptidomimetics

In connection with efforts to build constrained peptidomimetics for the endocrine hormone TRH, a general strategy for the construction of bicyclic lactam peptide building blocks has been developed. This strategy used an anodic amide oxidation to selectively functionalize proline and then an olefin metathesis to build the desired lactam constraint. The route described provides a single approach for synthesizing both fully functionalized TRH analogs having seven- and eight-membered ring lactam constraints, as well as six- and seven-membered ring lactam analogs without the sidechain on the central amino acid.     

Chiral Synthesis of an α-Tetrasubstituted Proline Derivative

An efficient approach for the synthesis of a new class of triazolophanes by 1,3-dipolar cycloaddition reaction of highly reactive organic azides with dialkynes using Cu(I)-catalyzed azide–alkyne cycloaddition methodology (“click chemistry”) has been developed. All the compounds were characterized by spectral and elemental analyses.     

4-烷基双环磷酸酯的合成研究

双环磷酸酯,即2,6,7-三氧杂-1-磷杂双环[2.2.2]辛烷1-氧化物的同系物,是哺乳动物的惊厥剂。惊厥活性产生于双环磷酸酯抑制神经递质 GABA 生理效应,是 GABA 的重要拮抗剂。这类化合物具有简单的刚性笼形结构,化学稳定性好,可作为有效的工具药。在各种类型双环磷酸酯的衍生物中,结构     

Enantioselective Synthesis of Quaternary Carbon Stereocenters by Asymmetric Allylic Alkylation: A Review

Quaternary stereocenters are of great importance to the three-dimensionality and enhanced properties of new molecules, but the synthetic challenges in creating quaternary stereocenters greatly hinder their wide use in drug discovery, organic material design, and natural product synthesis. The asymmetric allylic alkylation (AAA) of allylic substrates has proven to be a powerful methodology for enantioselective formation of structure skeletons bearing single or more quaternary carbon centers in modern asymmetric organocatalysis. AAA has certain advantages in constructing the tetrasubstituted stereocenters, including but not limited to mild reactive conditions, effective reaction rates, new functional group introduction, and carbon chains length extension. This review outlines the key considerations in the application of AAA reactions and summarizes the recent progress of AAA reactions in the enantioselective synthesis of products containing quaternary stereocenters. Meanwhile, a detailed discussion of the AAA reactions such as ligands, scope of substrates, transformations and the general reaction mechanisms is also provided. We hope this review could stimulate further advances in much broader areas, including organic synthesis, asymmetric catalysis, C−H activation, and symmetrical pharmaceutical chemistry.     

Synthesis and Structure of A Novel Caged Bicyclic Phosphate Flame Retardant

IntroductionThe ecological safety of polymer flame retardant has become a major subject in the modern polymer industry, and there is an international demand for the control of polymer flammability without the use of halogenated additives. Consequently, current research is mainly focused on looking for environmental friendly additives in the form of organophosphorus compounds, which are being thought as the alternatives of the halogen containing flame retardants1. Among the organophosphorus fla…     

A practical total synthesis of (+)-isogalbulin and (+)-galbulin

A practical total synthesis of the natural products (+)-isogalbulin and (+)-galbulin has been achieved in 10 steps from readily available 3-(3,4-dimethoxyphenyl)propanoic acid. The total yields were 12.3% and 12.9%, respectively. The key steps involved Evans asymmetric alkylation, Sharpless asymmetric epoxidation, and a highly regioselective opening of 1-benzyloxy-2,3-epoxides with an organoaluminum ate-complex formed by Me₃Al and n-BuLi.     

Multicomponent Synthesis of Chiral Bidentate Unsymmetrical Unsaturated N‐Heterocyclic Carbenes: Copper‐Catalyzed Asymmetric CC Bond Formation

A multicomponent strategy was applied to the synthesis of chiral bidentate unsaturated hydroxyalkyl‐ and carboxyalkyl‐N‐heterocyclic carbene (NHC) precursors. The newly developed low‐cost chiral ligands derived from amino alcohols and amino acids were evaluated in copper‐catalyzed asymmetric conjugated addition and asymmetric allylic alkylation, which afforded the desired tertiary and quaternary carbon stereocenters with excellent regio‐ and enantioselectivities (up to 99:1 e.r.).     

A New Synthesis of trans-3,4-Dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydro-7,12-dimethylbenz(a) anthracene

A facile synthesis of trans-3,4-dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydro-7,12-dimethylbenz(a) anthracene 1 ; a highly carcinogenic metabolite of 7,12-dimethylbenz(a) anthracene (DMBA) have been described.     

Synthesis of new bicyclic lactam peptidomimetics by ring-closing metathesis reactions

An efficient and versatile synthetic method for the preparation of new fused bicyclic lactams 3a and 3b is described. The spirane cyclopentane nucleus was easily installed by diallylation of the pyroglutamate derivative 18 followed by ring-closing metathesis (RCM). A more practical and stereoselective method for the allylation of the α-methoxy carbamate 21, involving the use of InCl₃ as a Lewis acid, was developed. In the crucial coupling reaction of the diastereomeric mixture of cis- and trans-pirrolidine derivatives 5a and 5b with N-Cbz vinyl phenylalanine only the cis isomer was found to react. An RCM reaction on the dipeptides 25a and 25b followed by catalytic hydrogenation, gave the final epimeric bicyclic lactams 3a and 3b. The same synthetic sequence on the model compound 7, lacking the spiro cyclopentane nucleus, is also reported.     

双环笼状取代倍半硅氧烷的合成与表征

以双环笼状含磷四配位硅为前驱体, 四甲基氢氧化铵为催化剂反应得到具有高度对称结构的双环笼状磷酸酯取代倍半硅氧烷, 通过红外光谱, ²⁹Si固体核磁共振谱, 质谱和X衍射光谱等手段确定了产物的结构和晶型. 热分析结果表明, 添加5%集磷硅为一体的倍半硅氧烷, 能使环氧树脂的分解温度提高45 ℃, 700 ℃时成炭量达到12.2%.     

Short and Efficient Synthesis of Oxazinone- and Thiazinone-Containing Bicyclic Heteroaromatic Aldehydes

Short and efficient route for the synthesis of oxazinone- and thiazinone-containing bicyclic heteroaromatic aldehydes, which involves the key step of palladium-catalyzed reductive carbonylation, is described. Overall routes for the synthesis of these aldehydes are short, versatile, and scalable with good yields of the product.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Asymmetric Synthesis of Bicyclic Diol Derivatives through Metal and Enzyme Catalysis: Application to the Formal Synthesis of Sertraline

Enzyme‐ and ruthenium‐catalyzed dynamic kinetic asymmetric transformation (DYKAT) of bicyclic diols to their diacetates was highly enantio‐ and diastereoselective to give the corresponding diacetates in high yield with high enantioselectivity (99.9 % ee). The enantiomerically pure diols are accessible by simple hydrolysis (NaOH, MeOH), but an alternative enzyme‐catalyzed ester cleavage was also used to give the trans‐diol (R,R)‐ 1 b in extremely high diastereomeric purity (trans/cis=99.9:0.1, >99.9 % ee). It was demonstrated that the diols can be selectively oxidized to the ketoalcohols in a ruthenium‐catalyzed Oppenauer‐type reaction. A formal enantioselective synthesis of sertraline from a simple racemic cis/trans diol 1 b was demonstrated.     

双环缩酮类信息素——Brevicomin和Fmntalin合成研究进展

介绍了双环缩酮类信息素——Brevicomin和Frontalin在立体选择性和非立体选择性合成中的各种方法。参考文献48篇。     

双环笼状四配位硅的合成及其结构表征

研究了以SiO₂为原料低温合成高反应活性的五配位硅酸酯, 并与1-氧代-1-磷杂-2,6,7-三氧杂双环[2.2.2]-4-氯甲基辛烷反应合成出具有对称结构的双环笼状四配位硅, 通过红外光谱、¹³C和²⁹Si固体核磁共振、质谱等测试手段确定了其结构. 热分析结果表明, 双环笼状四配位硅在700 ℃的失重仅为19.98%, 且炭层呈密实片层状, 说明目标产物具有优异的热稳定性和成炭性质.     

Enantioselective Pd‐Catalyzed Allylic Alkylation Reactions of Dihydropyrido[1,2‐a]indolone Substrates: Efficient Syntheses of (−)‐Goniomitine, (+)‐Aspidospermidine,and (−)‐Quebrachamine

The successful application of dihydropyrido[1,2‐a]indolone (DHPI) substrates in Pd‐catalyzed asymmetric allylic alkylation chemistry facilitates rapid access to multiple alkaloid frameworks in an enantioselective fashion. Strategic bromination at the indole C3 position greatly improved the allylic alkylation chemistry and enabled a highly efficient Negishi cross‐coupling downstream. The first catalytic enantioselective total synthesis of (?)‐goniomitine, along with divergent formal syntheses of (+)‐aspidospermidine and (?)‐quebrachamine, are reported herein.