Functionalization of C,C-palladacycles:application in the synthesis of functional molecules

Significant advancements have been achieved in the field of C,C-palladacycles functionalization in recent decades,which have greatly contributed to the synthesis of intricate drug molecules,natural products,innovative materials,and chiral ligands.Additionally,these advancements have led to the establishment of highly efficient and atom-economic synthetic processes.Based on the differences in the C–Pd bonds,C,C-palladacycles can be further classified into several main types:C(aryl),C(alkyl)-,C(aryl),C(aryl)-,C(aryl),C(vinyl)-,and C(alkyl),C(carbonyl)-palladacycles.This minireview will highlight the recent advances in the synthesis of functional molecules through the functionalization of different C,C-palladacycles,and we hope this survey will inspire future strategic developments for C,C-palladacycle catalysts and their synthetic application.

Enantioselective and stereodivergent hydromonofluoroalkylation of conjugated and remote diene

Because of the widespread applications of optically active alkyl fluorides in medicinal and agro chem-icals,enantioselective and even stereodivergent construction of alkyl fluorides remains highly desirable but underdeveloped.Transition-metal-catalyzed asymmetric hydrofluoroalkylation of readily available di-enes represents a novel route to achieve this goal,yet receives scarce study.Here we report an intrigu-ing palladium-catalyzed enantioselective hydromonofluoroalkylation reaction of conjugated dienes.Both monosubstituted and internal dienes proceed well with the transformation and furnish alkyl fluorides in generally>80%yield and>90%ee.A stereodivergent hydromonofluoroalkylation protocol via Pd/Cu co-catalysis is also established for the access to all four stereoisomers of corresponding moieties bear-ing a fully-substituted F-stereogenic center and vicinal tertiary carbon center.In addition,asymmetric migratory hydromonofluoroalkylation of skipped dienes is developed to realize the direct allylic C-H flu-oroalkylation.A compound library of enantioenriched cyclic fluorides is thus built to highlight the trans-formation potential of present methodology.

Catalytic asymmetric synthesis of 1,4-enynes

1,4-Enyne units are ubiquitous skeletons in biologically active molecules and natural products.Especially,they represent versatile building blocks for abundant downstream derivatizations via controllable modifications of both alkene and alkyne units independently.Recently,great efforts have been made to establish efficient protocols to achieve optically active 1,4-enynes.Considering the enormous application potential of enantioenriched 1,4-enyne units but no related review on this topic has been described,here we aim to provide a comprehensive summary on the catalytic methods established for enantioselective constructions of these intriguing skeletons.According to the reaction types,this review is divided into five parts,including asymmetric allylic substitution,asymmetric propargylic substitution,asymmetric alkynylallylic substitution,asymmetric hydroalkynylation and asymmetric 1,2-addition of alkynes to conjugated imines or ketones.

Homeostasis of Brassinosteroids Regulated by DRL1, a Putative Acyltransferase in Arabidopsis

Brassinosteroids （BRs） play essential roles in regulating various aspects of plant growth and development and in responding to diverse environmental cues, and their metabolism is an important way to regulate their homeosta-sis in plants. Here, we identified a dominant mutant, dwarf and round leaf-1 （drll-D）, which exhibits weak BR-deficient or BR-insensitive mutant phenotypes, including short and round leaves, prolonged senescence, dwarfed shape, and altered expression levels of the BR-responsive genes. Hypocotyl length and root inhibition assays suggest that the drll-D mutant responds to BRs normally, but has decreased BR signaling outputs. The endogenous levels of several BRs, includ-ing typhasterol （TY）, 6-deoxotyphasterol （6-deoxoTY）, and 6-deoxocastasterone （6-deoxoCS）, are significantly lower in the drll-D mutant than in the wild-type. The DRL1 gene encodes an acyltransferase and is widely expressed in leaves, roots, flowers, and siliques. Plants without DRL1 and its homologs are larger with an enhanced BR signaling. The expres-sion of DRL1 was induced by eBL and inhibited by ABA. DRL1 is involved in the BR metabolism likely by catalyzing the BR conjugation through esterification, which plays important roles in regulating the BR homeostasis and responding to abiotic stresses in Arabidopsis.

Recent Advances in Radical-Mediated C-C Bond Fragmentation of Non-Strained Molecules

The carb on-carbon (C-C) σ-bonds construct the fundame ntal frameworks of organic molecules. The direct fun ctionalization of C-C bonds represe nts one of the most efficient and step-economical transformations in synthetic chemistry. The past few decades have witnessed the fast development of transition-metal mediated C-C bond activation.

Synthesis and combined properties of novel fluorinated cationic surfactants derived from hexafluoropropylene dimer

Three novel fluorinated cationic surfactants were prepared by adopting perfluoro-2-methy1-2-pentene as raw substrate. The as-obtained fluorinated cationic surfactants exhibited excellent surface properties, all of them can reduce the surface tension of water to below 20.00mN/m at the critical micelle concentrations （CMC）. The incorporation of SDS, AOS, APG or LAB into 2-（4-（3,3,4,4,5,5,5-heptafluoro- 2,2-bis（trifluoromethyl）pentyl）benzamido）-N,N-dimethylethana-mine oxide 4a could generate much lower CMC and surface tension value at the CMC than individual 4a. Especially, the surface tension values of that combined APG/4a can be reduced to 17.31 mN/m. The excellent surface activities and their remarkable compatibility to various types of hydrocarbon surfactants make them as sustainable alternatives to PFOA （perfluorooctanoic acid, C7F15CO2H） and PFOS （perfluorooctane sulphonate, C8F17SO3X, with X = K, Na, H）.

Regioselective introduction of vinyl trifluoromethylthioether to remote unactivated C(sp^3)–H bonds via radical translocation cascade

Described herein is an efficient protocol for the regioselective introduction of a vinyl trifluoromethylthioether to remote unactivated C(sp3)–H bonds.The cascade process involves the vinyl radical-mediated 1,5-hydrogen atom transfer(HAT)and remote vinyl migration.During the transformation,inert C–H and C–C bonds are consecutively cleaved under mild conditions.The reaction features good functional group tolerance,broad substrate scope,and high regio-/stereo-selectivity.

A new approach to the bicyclo[3.3.1]nonane framework of huperzine A-like molecules via palladium-catalyzed intramolecular γ-arylation

In our synthetic studies toward huperzine A, a diastereoselective α′-alkylation of the α-amido-γ-methyl hexenone 4 was realized through a dianion intermediate which significantly enhanced the reactivity. Under the attempted Heck reaction conditions, an unexpected and unprecedented palladium-catalyzed intramolecular γ-arylation of 3 was observed, which generated 18 with bicyclo[3.3.1]nonane framework in satisfactory yield.

Enantioselective synthesis of functionalized fluorinated dihydropyrano[2,3-c]pyrazoles catalyzed by a simple bifunctional diaminocyclohexane-thiourea

Enantioselective synthesis of functionalized fluorinated dihydropyrano[2,3-c]pyrazoles has been achieved via a diaminocyclohexane-thiourea catalyzed cascade Michael addition and Thorpe-Ziegler type cyclization in high yields （up to 98%） with moderate to good enantioselectivity （up to 90% ee）.

Asymmetric epoxidation of α,β-unsaturated ketones using α,α-diarylprolinols as catalysts

Asymmetric epoxidation of α,β-unsaturated ketones has been extensively studied and several important procedures have been developed in the last decade. This review addresses the most significant advances in asymmetric epoxidation of α,β-unsaturated ketones using proline-derived α,α-diarylprolinols as catalysts. Special attention has been paid to the enantioselective epoxidation of chalcones, α,β-unsaturated trifluoromethyl, trichloromethyl ketones and β,γ-unsaturated α-keto esters based on the reseach of our group.

Radical Heteroarylalkylation of Alkenes via Three-Component Docking-Migration Thioetherification Cascade

A novel,rational-designed approach to access various heteroaryl-substituted alkyl thioethers was developed via docking-migration cascade process.By utilizing three components involving alkene,dual-function reagent,and thioetherificating reagent,radical heteroarylalkylation of alkenes followed by thiolation of the alkyl radical intermediates proceeded smoothly,manifesting well compatibility of substrates and cascade transformations.Furthermore,this protocol also features mild conditions,broad substrate scope,and wide product diversity.

Expedient Synthesis of （R）-Curcuphenol： A Chiral Pool Strategy

Curcuphenol 是有多样的 bioactivities 的有趣的 sesquiterpenoid。一条简明、可伸缩的合成线路的探索仍然具有在许多不对称的全部的综合体被完成了的恶意的意义。我们从香茅醛报导(R)-curcuphenol 的有用不对称的合成，它在全面六步的合成展示二仅仅纯化操作。

Design and synthesis of the novel branched fluorinated surfactant intermediates with CF_3CF_2CF_2C(CF_3)_2 group

Perfluorooctanoic acid(PFOA) or perfluorooctane sulphonate(PFOS) was one of the most prominent fluorosurfactants and applied widely in firefighting and daily chemical, etc. However, these surfactants have recently been identified as toxic and undegradability in the environment. Developing an efficient approach to environment-friendly fluorosurfactants is essential. A fluorocarbon branched chain strategy was adopted to develop/PFOS substitutes. A series of intermediates of novel branched fluorinated surfactants with CF_3 CF_2CF_2C(CF3)_2 group were synthesized from perfluoro-2-methyl-2-pentene. All the steps were mild, easy-handled and cheap. It is expected to be a very significant direction for the development of non-bioaccumulable alternatives of PFOA or PFOS.

Direct Double Electrophilic Fluorination of Allenoic Acids and Tosylamides to Give 1,1-Difluoroallylic Heterocyclic Compounds

A novel and facile preparation of l,l-difluoroallyl substituted five-membered lactones or pyrrolidines in mod- erate yields through direct double electrophilic fluorination of 4,5-allenoic acids or tosylamides with SelectfluorTM F-TEAD-BF4 is described.

Highly Efficient Synthesis of Unsymmetrical 3,3＇-Bis（1H-indol-3-yl）methanes in Water

A simple and practical approach for the preparation of unsymmetric bis（indolyl）methanes （BIMs） was realized by Lewis acid InBr3-catalyzed Friedel-Crafts reaction of indoles with 3-indolyl-substituted phthalides in water.

Efficient Synthesis of Isoquinolines by AgNO3-Catalyzed Sequential Imination-Annulation of 2-Alkynyl Aldehydes with Ammonium Bicarbonate

An operationally simple approach for the tandem synthesis of isoquinolines by the reaction of o-alkynylalde- hydes with ammonium bicarbonate via Ag-catalyzed 6-endo-dig ring closure is described. The reaction conditions and the scope of the reaction are examined, and a variety of substituted isoquinolines are prepared in moderate to excellent yields.

Synthesis of Substituted Naphthalenes by 1,4-Palladium Migration Involved Annulatlon w,th Internal Alkynes

The palladium catalyzed annulation of 1-bromo-2-vinylbenzene derivatives with internal alkynes was realized for the efficient synthesis of substituted naphthalenes. A controllable aryl to vinylic 1,4-palladium migration process is the key for success.

Organophosphine bearing multiple hydrogen-bond donors for asymmetric Michael addition reaction of 1-oxoindane-2-carboxylic acid ester via dual-reagent catalysis

Multiple hydrogen bonds containing nucleophilic phosphines derived from dipeptide dual-reagents catalyzed asymmetric Michael addition reactions between indene esters and activated olefins in high yields and good to excellent enantioselectivities under mild reaction conditions.The success of current highly selective reactions should provide inspiration for expansion to other reactions and would open up new paradigms for the synthesis of indanone derivatives bearing chiral quaternary carbon centers.

Development of Biomimetic Synthesis of Propindilactone G

of main observation and conclusion The natural product propindilactone G is a complex Schisandra nortriterpenoid with a unique 5/5/7/6/5 pentacyclic framework.This full paper describes the development of concise biomimetic synthesis of propindilactone G from a known steroid lactone.The key C19-OH intermediate was synthesized via Breslow and Suarez radical remote C—H functionalizations.Wagner-Meerwein rearrangement was subsequently utilized for the expansion of the B ring.To invert the configuration of the C1O tertiary alcohol,an intramolecular peroxide cyclization catalyzed by BF3-Et2O was devised.The 5/5 fused lactone system was then assembled in a biomimetic transesterification/oxa-Michael addition sequence.Our work should provide experimental support for the proposed biosynthetic pathway and facilitate investigation of the biological activities of pro pindilactone G.

A Formal Synthesis of Iridoid 9-Deoxygelsemide

iridoid 9-deoxygelsemide 的正式全部的合成被完成了。我们的途径作为开始材料展示(S)-carvone 的使用，构造 functionalized cyclopentane 核心的 Favorskii 重新整理，介绍 endocyclic 的 Chugeav 消除加倍契约，和 epoxide 的戒指洞反应造第二枚五成员的戒指。