An improved synthesis of (-)-7-isopropyl-cis-l-amino-2-indanol the chiral auxiliary for 6π-azaelectrocyclization

(-)-7-Isopropyl-cis-1-amino-2-indanol,a key chiral auxiliary and ligand in the highly stereo-selective asymmetric 6π-azaelectrocyclization, has been prepared previously by two methods.Each however involved using of one extreme condition, i.e.high temperature or high pressure,for the respective reaction.A modified reaction route employed mild condition for synthesis was presented in this report.     

Synthesis of Analogues of the Antitumor （1→6）-Branched （1→3）-Glucohexaose

β-D-Glcp-(1→）3-[β-D-Glcp-(1→6)-]α-D-Manp-(1→3)-β-D-Glcp-(1→3)-[β-D-Glcp(1→6)-]D-Glcp(18)and β-D-Glcp(1→3)-[β-D-Glcp(1→6)-]α-D-Manp-(1→3)-β-D-Glcp(1→3)-[β-D-Glcp(1→6)-]β-D-Glcp-D-(1→3)-Glcp-1→OM3(29)were synthesized as the analogues of the immunomodulator β-D-Glcp-(1→3)-[β-D-Glcp(1→6)-]α-D-Glcp(1→3)-β-D-Glcp(1→63)-[β-D-Glcp(1→6)-]D-Glcp through coupling of trisaccharide donors 9 with trisaccharide acceptor 16 and tetrasaccharide acceptor 27 followed by deprotection,respectively.     

A concise formal stereoselective total synthesis of （-）-swainsonine

A short formal stereoselective synthesis of （-）-swainsonine （1） is described. Our synthesis started with the versatile building block （R）-3-benzyloxyglutarimide 5. Through controlled regioselective reduction, Ley＇s-sulfone chemistry （N-α-sulfonylation and ZnCl2-catalyzed N-α-amidovinylation）, an RCM reaction, and an amide reduction, the synthesis of unsaturated indolizidine （8R,8aS）-3 has been achieved in five steps. The indolizidine （8R,8aS）-3 is an advanced intermediate toward the synthesis of （-）-swainsonine （1）.     

A Short and Stereoselective Synthesis of the （-）-（5R, 6S）-6-Acetoxy-hexadecane-5-olide

(-)-(5R, 6S)-6-Acetoxyhexadecan-5-olide 1, a natural mosquito attractant pheromone,was synthesized from readily available aldehyde 2 and cyclopentanone 3 using L-proline-catalyzed asymmetric aldol reaction as the key step.     

Stereoselective Synthesis of （E）-1, 3-Enynyl Bromides via Pd／Cu-cata-lyzed Cross-coupling Reaction of （Z）-α-Bromovinylstannanes

(Z)-α-Bromovinylstannanes undergo the cross-coupling reaction with alkynyl iodides in the presence of Pd(PPh3)4 and CuI in THF at room temperature to afford stereoselectively (E)- 1, 3-enynyl bromides in good yields.     

Stereoselective Synthesis of （R）-Salmeterol via Asymmetric Cyanohydrin Reaction

The authors described a short and highly enantioselective route to （R）-salmeterol involving asymmetric synthesis of cyanohydrin followed by nucleophilic substitution with 6-（4-phenylbutoxy） hexyl methanesulfonate.     

Microwave-assisted reactions： Three-component process for the synthesis of 2-amino-2-chromenes under microwave heating

2-Amino-2-chromenes are class of heterocycles that posses considerable interest as pigments,cosmetics,potential agrochemicals and being the main constituents of many natural products.Although,they are generally prepared either under conventional heating,benign reagents or very recently,a three component condensation in poly-ethylene glycol-water in the presence of nanosized magnesium oxide,most of these methods require prolonged reaction time,reagents in stoichiometric amounts and generate moderate yield...     

π—πStacking Force in the Solid Structure of Mixed—Metal complexes：Zn（phen）2MS4（M=W,Mo）

1 INTRDUCTION Supramolecular chemistry of coordination compounds is the subject of intense research in recent years[1a]. Besides covalent bond, some weaker intermolecular interactions such as S…S con- tacts[1b], weak coordination, hydrogen bonding and pp stacking[1c] are efficient organising forces in supramolecular architecture. The properties of solid state materials may be quite different from those of isolated molecule due to the intermolecular interaction. In previous work[1d], we …     

One-pot synthesis of 2-（1-acyloxypentyl） benzoic acids

A one-pot synthesis of 2-（1-acyloxypcntyl） benzoic acids by trapping the carboxylatc/alkoxide dianion with acylating reagents following Grignard addition with n-BuMgBr to 2-formylbcnzoic acid was described. Compared with routine synthetic method, this novel procedure has the advantage of convenient operation and higher yields.     

One-pot Sequential Reaction for the Synthesis of Polysubstituted 3-（3-Nitro-2-phenylchroman-4-yl）-3-arylaminoacrylates

The one-pot sequential reaction of arylamines, methyl propiolate and 2-aryl-3-nitrochromenes without any catalyst in refluxing ethanol afforded the polysubstituted 3-（3-nitro-2-phenylchroman-4-yl）-3-arylaminoacrylates in good yields and with high diastereoselectivity. Reaction mechanism was believed involving the initial formation of β-enamino ester and sequential Michael addition.     

Synthesis and Crystal Structure of 1-（N,N-Di-（p-toluenesulfonyl））-amino- 2-（N＇-p-toluenesulfonyl）-amino-3,5-dinitrobenzene

The title compound, 1-(N,N-di-(p-toluenesulfonyl))-amino-2-(N'-p-toluenesulfonyl)-amino-3,5-dinitrobenzene, was synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in orthorhombic, space group Pna21 with a = 13.723(2), b =25.354(4), c = 8.6565(12)(A), V= 3011.9(8)(A)3, Z= 4, Mr = 660.68, F(000) = 1368, Dc = 1.457 g/cm3,μ = 0.309, the final R = 0.0609 and wR = 0.1042. The H atom of N2-H group, which is the unique recognition site to anion, is enveloped by two oxygen atoms and one benzene from two and one p-toluenesulfonyl moieties, respectively.     

（E）-α-Bromovinylselenides as Convenient Precursors for Stereose-lective Synthesis of Trisubstituted Alkenes

Based on the different reactivity of selanyl and bromo groups,(E)-α-bromovinylselenides can undergo sequential cross coupling reactions with nucleophiles in the presence of transition metal complexes to form two carbon-carbon bonds in the same olefinic carbon leading to trisubstituted alkenes stereoselectively in good yields.     

Preparation and Crystal Structure of 3-（2-Hydroxyphenyl） -6- （4-nitrophenyl）-7H- 1,2,4-triazolo[3,4-b][1, 3,4]thiadiazine

Introduction3,6- Disubstituted- 7H- 1 ,2 ,4- triazolo[3,4- b][1 ,3,4]thiadiazines are amongst the various hete-rocycles that received considerable attention duringthe last two decades as potential biologically activeagents.This kind of N- bridged heterocycles hasbeen reported to possess the wide spectrum of bio-logical properties,such as antimicrobial[1] ,an-tibacterial,antifungal[2 ] ,antiinflammatory[3 ] ,di-uretic[4] ,anthelmintic,and analgesic properties[5] .They can be also used as plant…     

Preparation and chiral recognition of a novel chiral stationary phase for HPLC,based on mono（6A-N- 1-（2-hydroxyl）- phenylethylimino-6A-deoxy）-β-cyclodextrin and covalently bonded silica gel

A novel chiral stationary phase （CSP） was prepared by immobilizing mono（6A-N-1-（2-hydroxyl）-phenylethylimino-6A- deoxy）-β-cyclodextrin onto the surface of silica gel via a longer spacer. This chiral stationary phase exhibited good enantioselectivity for a variety of chiral compounds under reversed-phase conditions.     

Synthesis of 1—（2′—Phenyl）cycloproply1—2,3—epoxypropan—1—ol as the Radical Precursor for the Kinetic Study of Oxiranylcarbinyl Radical

We have successfully synthesized 1-(2′-Phenyl)cycloproply1-2,3-epoxypropan-1-ol 3,which will be applied to the kinetics study of oxiranylcarbinyl radical.     

A facile stereospecific synthesis of （Z）-2-sulfonyl-substituted 1,3-enynes via Sonogashira coupling of （E）-α-iodovinyl sulfones with 1-alkynes

(E)-a-Iodovinyl sulfones 1 underwent the Sonogashira coupling reactions with terminal alkynes 2 in piperidine at room temperature in the presence of 5 mol% of Pd(PPh3)4 and 10 mol% of CuI to stereospecifically afford the corresponding (Z)-2- sulfonyl-substituted 1,3-enynes 3 in high yields.     

Synthesis of β-（ 1→6）-Branched （ 1→3）-Glucononaoside with Alter-nate β- and α-Bonds in the Backbone

Lauryl glycoside of β-D-Glcp-(1→3)-[β-D-Glcp-(1→6)-]α-D-Glcp-(1→3)-β-D-Glcp-(1→3)-[β-D-Glcp-(1→6)-]α-D-Glcp-(1→3)-β-D-Glcp-(1→3)-[β-D-Glcp-(1→6)-]β-D-Glcp was synthesized through 3 3 3 strategy. 3-O-Allyl-2,4,6-tri-O-benzoyl-β-D-glucopyranosyl-(1→3)- -[2, 3, 4, 6-tetra-O-benzoyl-β-D-glucopyranosyl-(1→6)-] 1,2-O-isopropylidene-α-D-glucofuranose was used as the key intermediate which was converted to the corresponding trisaccharide donor and acceptor readily.     

Stereoselective Syntheses and Biological Properties of （E）-α- （Methoxyimino） -2-[1-（aryloxy） methyl] -benzeneacetates

IntroductionStrobilurins have been an important class of agri-cultural fungicides,and this class of fungicides is basedon a group of naturally leading derivatives of(E)-meth-ylβ-methoxyacrylate,such as strobilurin A,oudeman-sin A,and myxothiazol A[1,2].T…     

Synthesis and Crystal Structure of 7α-[（R）-1-Hy droxyl-1-methyl-3-（ thien-2-yl）-propyl]-6,14-endoethanotetrahydrothebaine

1 INTRODUCTION Opioid analogues still remain important drugs for the relief of severe pain and morphine is still the drug of choice in such situations. For many years, the search for new centrally acting opioid deriva- tives with pain-relieving properties and without un- desired side effects, such as addiction, obstipation, etc., has been the goal of a large number of scien- tists[1-3]. Consequently, a wide variety of modifyca- tions of the well-known alkaloids morphine, codeine and thebai…