Stereoselective Synthesis of 2-Chloro-4-Substituted-phenyl-5,5-Dimethyl-1,3,2-Dioxaphosphorinan-2-(Thi)ones

The stereoselective synthesis of 2 -chloro-4- substituted-phenyl-5, 5-dimthyl- 1,3, 2-dioxaphsphorinan- 2 - (thi) ones is described. only single trans-isomers were obtained when 1-substituted-phenyl-2, 2 -dimethyl-1,3 -propanediols (1) reacted with POCl3. But the stereoselectivity of cyclization reaction between (1) and PSCl3, depended greatly upon the reaction condition. The configurational assignments and the ratio of cis-/trans-diastereoisomers of the products were performed on the basis of 1 HNMR, 31PNMR and IR spectra and confirmed by X-ray diffraction

A Novel Stereoselective Synthesis of 8-O-4' Neolignans

1-(4-hydroxy-3-methoxyphenyl)-2-(4-formyl-2-methoxyphenoxy)-propane-1,3-diol, A 8-O-4’ neolignan, has been stereoselectively synthesized in eight steps from ferulic acid, and the directly cis opening of epoxide in epoxidation and Mitsunobu reaction were used ingeniously as two key steps with high stereoselectivity.

An Efficient and Stereoselective Synthesis of (-)-Massoialactone

An efficient and stereoselective four Step Synthesis of (-)Massoialactone (1) is described.The key step intolves deoxygenation of one α,β - unsatoted carbonyl group in compound

The Formal Stereoselective Synthesis of(+)-Preussin

The stereoselective synthesis of (+)-preussin has been achieved by utilizing the Sharpless asymmetric epoxidation of the divinylcarbinol(3) and the oxidative cyclization of 9with PDC as the key steps.

Studies on Agarofurans Ⅱ.Stereoselective Synthesis of 1α-and 1β-Methyl Agarofuran

1α- and 1β-methyl agarofuran 1 and 2 were stereoselectively synthesized. the key intermediates being synthesized through stereoselective Robinson annulation.The conjugated double bond was redined in an improved way. Alkylation of imine 7 with enone 8, 9, 10 was

'STEREOSELECTIVE SYNTHESIS OF TRISIJBSTITUTED ALKENES VIA,TITANOCENOCYCLES

By previously reported modified Masai-Rausch method of synthesizing titanocenocycles,followed by acid hydrolysis,trisubstituted al-kenes were synthesized,yields obtained are higher than that reported in literatures.Starting from unsymmetrical alkyne substrates,twelve different types of substituted alkenes were synthesized,among which only two were found single component,others were of mixed isomers.Beside conventional analytical methods,the NMR spectral analysis of titanocenoheterocycle intermediates and the products were used to identify the isomeric structures as well as their relative contents.

Stereoselective Synthesis of syn- and anti-3a-Hydroxyl-1, 2, 3, 3a, 8, 8a-hexahydropyrrolo[2,3-b] indole-2-carboxylic Acid

The structure of syn- and anti-Nb-(p-toluenesulfonyl)-3a-hydroxyl-1, 2, 3, 3a, 8, 8a-hexahydro pyrrolo[2,3-b] indole-2-carboxylic t-butyl ester was stereoselectively synthesized by oxidative ring formation of Nb-(p-toluenesulfonyl)-L-tryptophan t-butyl ester in methylene chloride containing dimethyldioxirane (DMDO), the p-toluenesulfonyl group and t-butyl group can be easily removed by sodium naphthalenide and trifluoroacetic acid, respectively.

Stereoselective Synthesis of (Z)-β-Aryltellurocinnamic Esters

ＳｔｅｒｅｏｓｅｌｅｃｔｉｖｅＳｙｎｔｈｅｓｉｓｏｆ（Ｚ）－β－ＡｒｙｌｔｅｌｌｕｒｏｃｉｎｎａｍｉｃＥｓｔｅｒｓ￥ＣｈａｎｇＱｉｕＺＨＡＯ；ＸｉａｎＨＵＡＮＧ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＨａｎｇｚｈｏｕＵｎｉｖｅｒｓｉｔｙ，Ｈａｎ...

The ERF transcription factor LTF1 activates DIR1 to control stereoselective synthesis of antiviral lignans and stress defense in Isatis indigotica roots

Lignans are a powerful weapon for plants to resist stresses and have diverse bioactive functions to protect human health.Elucidating the mechanisms of stereoselective biosynthesis and response to stresses of lignans is important for the guidance of plant improvement.Here,we identified the complete pathway to stereoselectively synthesize antiviral(-)-lariciresinol glucosides in Isatis indigotica roots,which consists of three-step sequential stereoselective enzymes DIR1/2,PLR,and UGT71B2.DIR1 was further identified as the key gene in respoJanuary 2024nse to stresses and was able to trigger stress defenses by mediating the elevation in lignan content.Mechanistically,the phytohormone-responsive ERF transcription factor LTF1 colocalized with DIR1 in the cell periphery of the vascular regions in mature roots and helped resist biotic and abiotic stresses by directly regulating the expression of DIR1.These systematic results suggest that DIR1 as the first common step of the lignan pathway cooperates with PLR and UGT71B2 to stereoselectively synthesize(-)-lariciresinol derived antiviral lignans in I.indigotica roots and is also a part of the LTF1-mediated regulatory network to resist stresses.In conclusion,the LTF1-DIR1 module is an ideal engineering target to improve plant Defenses while increasing the content of valuable lignans in plants.

Stereoselective synthesis of the 3,6-branched Fuziα-glucans up to 15-mer via a one-pot and convergent glycosylation strategy

A family of the 3,6-branched Fuziα-glucans including the pentasaccharide repeating unit as well as its di-and trimers were efficiently achieved via a one-pot and convergent glycosylation strategy.All the protectedα-glucans up to 15-mer were assembled with high yields and excellentα-stereoselectivity,which was secured by the synergisticα-directing effects of the Tol SCl/Ag OTf promotion system and the stericβ-facial shielding of bulky saccharide residues linked at the 6-O-position of glucosyl donors.Moreover,the 3,6-branched architecture of glycosyl donor was revealed to be more favorable for theα-selective glucosidation of primary hydroxyl group,especially in the case of large oligosaccharide acceptor.The structurally well-defined syntheticα-glucans would be useful for various biological studies.

An Efficient and Simple Method for Stereoselective Synthesis of N-Substituted Iminosugars from D-Xylose Derivative

A series of new N-substituted iminosugars were successfully synthesized through a general synthetic route from D-xylose derivative.This approach provided a convenient access to the synthesis of N-alkylated iminosugars as po-tential glucosidase inhibitors,which included a reaction of reductive amination.Various N-alkylated iminosugars were prepared in good yields with high stereoselectivity.

Enantioselective Aldol Reactions of Aliphatic Aldehydes with Singh’s Catalyst

Aldols from aliphatic aldehydes had been synthesized enantioselectively using Singh’s catalyst. Self and crossed aldol reactions with several linear aldehydes were performed.

Trisubstituted alkenes featuring aryl groups:stereoselective synthetic strategies and applications

In recent years,the synthesis and application of alkenes have attracted increased attention.Triphenylethenes(TriPEs)have lower molecular torsion than tetraphenylethenes(TPEs),which helps to balance the degree of conjugation and the aggregation-induced emission(AIE)effect.The geometry of double bonds has a significant impact on luminescence.Therefore,it is essential to provide a comprehensive summary of the stereoselective synthetic strategies for trisubstituted alkenes.In this review,common strategies for the stereoselective synthesis of alkenes are described,with an emphasis on the origin of stereoselectivity and the types of substrates.In addition,the AIE properties of TriPE and its applications in optoelectronic devices,stimuli-responsive materials,sensors,and therapies were discussed.

Methodology-driven efficient synthesis of cytotoxic(±)-piperarborenine B

The evolution of synthetic design toward the efficient synthesis of cyclobutane natural product(±)-piperarborenine B is demonstrated.Taking the advantages of good functional group compatibility of contractive synthesis of cyclobutanes from pyrrolidines,stereoselective synthesis of unsymmetric highly functionalized cyclobutanes core of(±)-piperarborenine B was realized in one step.Also,an unprecedented carboxylic acid assisted-diastereoselective Kracho decarboxylation/transmethylation features a new strategy for a non-symmetrical cyclobutane core.The synthesis of(±)-piperarborenine B illustrates the advancement of methodology resulting in the improvement in synthetic efficiency.

Stereodefined tetraarylethylenes:Synthesis and applications

Luminescent materials with efficient aggregate-state emissions are of growing interest due to their widespread applications in chemo-/biosensing and optoelectronic devices.Aggregation-induced emission(AIE)opens a new avenue for the applications of aggregate-state luminescent materials.Among the AIE luminogens(AIEgens),tetraarylethylenes(TAEs)are typical AIEgens with a simple molecule scaffold and could be utilized as a framework for further elaboration,enabling structure-property-function relationship studies and multi-functional applications.Since the existing approaches for the preparation of tetraarylethenes(TAEs)typically produce stereoisomeric mixtures,stereoselective synthesis of tetraarylethenes with desired geometry is a great challenge.In this review,we systematically compile the synthetic methodologies for the construction of TAEs in excellent regio-and stereoselectivities.The virtues and limitations of each methodology are discussed in detail as well.Meanwhile,the applications and the differences of properties between TAEs stereoisomers are introduced.