(Z)-a-Selanyl Alkenyl Grignard Reagents as Convenient Precursors for Stereoselective Synthesis of Trisubstituted Alkenes

Z)-a-Selanyl alkenyl Grignard reagents 2 were prepared conveniently by treatment of a-bromovinylselenides 1 with magnesium filings in THF. Intermediates 2 were reacted with alkyl iodides in the presence of CuI or Pd(PPh3)4 to afford (Z)-1,2-disubstituted vinylselenides 3, which were cross-coupled with Grignard reagents in the presence of (PPh3)2NiCl2 to give trisubstituted alkenes 4 stereoselectively in good yields.

Reaction of Polymer-supported Selenovinyl Bromide with Grignard Reagents: A Facile Route to the Synthesis of (E)-1, 2-Disubstituted Olefins

Polymer-supported selenovinyl bromide, easily prepared from polymer-supported selenenyl bromide with acetylene, reacts with different Grignard reagents using a step-by-step strategy to obtain （E）-1, 2-disubstituted ethenes in good yields.

Studies on New Additions to 5-Methoxy-2 (5H)-Furanone: 1, 4-Addition of Grignard Reagents, and 1,3-Dipolar Cycloaddition of Silyl Nitronates

1,4-Addition reaction of Grignard's reagent to 5-methoxy-2(5H)-furanone 1 was accomplished. which provided a new possible route for synthesizing beta -alkyl-Y-alkyloxy-Y-butyrolactone. A novel concise method of preparing fused heterocyclic compounds was offered by 1,3-dipolar cycloaddition reaction of silyl nitronates to 1.

Synthesis of C-Glucosides from Grignard Reagents Prepared by Activated Magnesium

l-α-biaomo-2,3,4,6-tetra-O-acetyl-D-giucopyranose reacts with Grignard eagents prepared frorn the acnvated magnesium under very mild condition to ellord C- glucosides in a very high yield compared with Grignard Reagent prepared from usual method.β-anomer predominates in the reaction, mixture The configuration of anomers was assigned by 13C NMR spectra.

Super-Grignard reagents(R_(2)Mg·LiCl)mediated covalent-anionic-radical polymerization capable of low?and reactive hydrogen compatibility

The precise synthesis of polymer with narrow molecular weight distribution(?)and well-defined architectures is very essential to exploring the functions and properties of polymer materials.Here,a universal polymerization method capable of low?and reactive hydrogen compatibility is reported by introducing super-Grignard reagents(R_(2)Mg?Li Cl)into polymer chemistry.Under mild conditions,various monomers,including nonpolar polystyrene and 4-methoxystyrene that cannot be initiated by Grignard reagents,and polar methacrylate,are successfully polymerized with full monomer conversion and low?.This approach is amenable to wide varieties of initiators,polymerization temperature,and feed ratio,which makes it attractive for applications in polymer synthesis.By adding methanol and water during the polymerization process,the reactive hydrogen compatibility of this method is confirmed,which makes this method avoid the rigorous restriction on polymerization conditions of anionic polymerization.Moreover,chain extension polymerization and block copolymerization are achieved and demonstrate the livingness of chain propagation,enabling the facile synthesis of well-defined macromolecular architectures.This work therefore expands the methodology libraries of living polymerization,which may cause inspirations to polymer science.

Synthesis of Osthole Derivatives with Grignard Reagents and Their Larvicidal Activities on Mosquitoes

The structure of osthole has been modified to improve its larvicidal activity against mosquitoes. A new efficient synthesis of osthole derivatives with Grignard reagents has been developed, which employs CuI and LiCI as pro- moters and covers a broad range of substrates to afford the corresponding products in mild to good yields （up to 83%）. Bio-activity evaluation showed that several products exhibited better activities than osthole.

Nickel-catalyzed cross-coupling reaction of alkynyl bromides with Grignard reagents

We describe a convenient method for the synthesis of 1,2-disubstituted acetylenes via a cross-coupling reaction of （bromoethynyl）benzene with Grignard reagents. The reaction of （bromoethynyl）benzene （1 mmol） with Grignard reagent （1.3 mmol） mediated by NiCl2 （4 mol%） and （p-CH3Ph）3P （8 mol%） in THF could produce 1,2-disubstituted acetylenes in good yields at room temperature.

Reaction of Alkanesulfinyl Chloride with Grignard Reagents： a Convenient Synthesis of Alkyl Sulfoxides

Alkyl sulfoxides were synthesized in good yields from the reaction of alkanesulfinyl chloride with Grignard reagents in the presence of zinc chloride.

Reaction of Grignard Reagents with Diethyl Perfluoroacyl (1-Cyanoethyl)phosphonates. Synthesis of Perfluoroalkylated α,β-Unsaturated Nitriles with Predominant Z-Selectivity

Diethyl (1-cyanoethyl) phosphorate 1 was reacted with n-butyl-lithium in tetrahydrofuran (THF) at - 78 °C and the resulting carbanion 2 reacted with perfluoroalkanoic add anhydride to afford perfluoroacylated phosphorate 3. Without isolation 3 was attacked by Grignard reagents giving perfluoroalkylated α, β-unsaturated nitriles in 46%-88% yields with high Z-stereoselectivity (Z: E = 89–62:11–38).

Addition of Organosamarium Reagents toα, β-Unsaturated Esters

Allylsamarium bromide reacts with Q, 6 -unsaturated esters and a -alkyloxy carbonyl α, β-unsaturated esters to give l,2-addition and 1 .4-addition products respectively.

Studies on Silicon-Containing Fragrance Raw Materials( Ⅲ )——The Addition of 5-Trimethylsilylcyclohex-3-enone with Grignard Reagent

The present paper narrates the addition of 5-trimethylsilylcyclohex-3-enone to Grig-nard reagent to give 1-substituted 5-trimethylsilylcyclohex-3-enol in a good yield. The stereochemistry of the addition reaction and their products are discussed.

POLYMER-SUPPORTED GRIGNARD REAGENT AND ITS USE IN THE FUNCTIONALIZATION OF POLYMER

Polymeric Grignard Reagent (PGR) based on the chloromethylated poly(ST-co-DVB) resinhas been prepared by means of anthracene-magnesium complex in THF (Anth-Mg-THF), andpolymer matrix with long polymethylene spacer was synthesized via the coupling reaction betweenPGR and α, ω-dibromoalkanes. Based on the studies of factors affecting the coupling, such ascatalyst,reaction time,the length of spacer etc.,this paper offers the optimal reaction conditionsand three typical experiment procedures. The mechanism for the formation and coupling reactionof PGR are also discussed.

Science Letters：A novel reduction of diketones with i-RMgBr catalyzed by Cp2TiCl2 and deoxygenation of sulfoxides by Cp2TiCl2／Al system

α-diketones and β-diketones react with Grignard reagents in the presence of a catalytic amount of Cp2TiCl2 to yield a-ketols and corresponding ketones respectively. Sulfoxides can be deoxygenated by Cp2TiCl2/Al system. The possible mechanisms are also discussed.

Novel Synthetic Method for Triacetylbenzene

Triacetylbenzene was prepared from tribenzimidazolium salt and Grignard reagent. The addition-hydrolysis reaction of tribenzimidazolium salt with Grignard reagent is reported and a novel method for preparation of triacetylbenzene is provided.

Synthesis of Novel Carbosilane Dendrimers with Myo-inositol Cores

The preparation of carbosilane dendrimers with cores of myo-inositol and the outmost periphery groups of allyl groups has been reported. By using alternate hydrosilylation and alkenylation reactions, the dendrimer have been carried up to the third generation with 48 allyl groups on the periphery.

A Novel Approach to Synthesis of α，β－Unsaturated Ketones

A new approach to the synthesis of α,β unsaturated ketones from 1,2,3 trimethyl benzimidazolium salt via the condensation reaction with aldehydes followed by the addition reaction of Grignard reagents with quaternary C=N bond was provided.

Synthesis of 2-Mercaptobenzaldehyde, 2-Mercaptocyclohex- 1-enecarboxaldehydes and 3-Mercaptoacrylaldehydes

A novel one-pot approach for the preparation of 2-mercaptobenzaldehyde, 2-mercaptocyclohex-l-enecarboxal- dehydes and 3-mercaptoacrylaldehydes [（Z）-3-mercapto-2-methyl-3-phenylacrylaldehyde, 3-mercapto-3-（o-tolyl）- acrylaldehyde）] starting from ortho-bromobenzaldehyde, 2-chlorocyclohex-l-enecarbaldehydes, （Z）-3-chloro-2- methyl-3-phenylacrylaldehyde and 3-chloro-3-（o-tolyl）acrylaldehyde is reported. The reaction of sulfur with the Grignard reagent of the acetal for the protection of the aldehyde group affords the title compounds through hydroly- sis with dilute hydrochloric acid in high yields.