Cross-Coupling Reaction of Alkenyl Sulfoximines and Alkenyl Aminosulfoxonium Salts with Organozincs by Dual Nickel Catalysis and Lewis Acid Promotion

In this article, the cross-coupling reaction (CCR) of exocyclic, axially chiral, and acyclic alkenyl (N-methyl)sulfoximines with alkyl- and arylzincs is described_. The CCR generally requires dual Ni catalysis and MgBr₂ promotion, which is effective in diethyl ether but not in THF. NMR spectroscopy revealed a complexation of alkenyl sulfoximines by MgBr₂ in diethyl ether, which suggests an acceleration of the oxidative addition through nucleofugal activation. The CCR of alkenyl sulfoximines generally proceeds in the presence of Ni(dppp)Cl₂ as a precatalyst and MgBr₂ with alkyl- and arylzincs with a high degree of stereoretention at the C and the S atom. CCR of axially chiral alkenyl sulfoximines with Ni(PPh₃)₂Cl₂ as a precatalyst and ZnPh₂ does not require salt promotion and is stereoretentive. The reaction with Zn(CH₂SiMe₃)₂, however, demands salt promotion and is not stereoretentive. CCR of axially chiral α-methylated alkenyl sulfoximines afforded persubstituted axially chiral alkenes with high selectivity. Alkenyl (N-triflyl)sulfoximines engage in a stereoretentive CCR with Grignard reagents and Ni(PPh₃)₂Cl₂. Ni-Catalyzed and MgBr₂-promoted CCR of E-configured acyclic alkenyl sulfoximines and aminosulfoxonium salts with ZnPh₂ and Zn(CH₂SiMe₃)₂ is stereoretentive with Ni(dppp)Cl₂ and Ni(PPh₃)₂Cl₂. CCRs of acyclic alkenyl sulfoximines and alkenyl aminosulfoxonium salts, carrying a methyl group at the α position, take a different course and give alkenyl sulfinamides under stereoretention at the S and C atom. CCR of acyclic, exocyclic, and axially chiral alkenyl sulfoximines has been successfully applied to the stereoselective synthesis of homoallylic alcohols, exocyclic alkenes, and axially chiral alkenes, respectively.     

Nickel-Catalyzed Anionic Cross-Coupling Reaction of Lithium Sulfonimidoyl Alkylidene Carbenoids With Organolithiums

The mechanistic platform for a novel nickel⁰-catalyzed anionic cross-coupling reaction (ACCR) of lithium sulfonimidoyl alkylidene carbenoids (metalloalkenyl sulfoximines) with organometallic reagents is reported herein, affording substituted alkenylmetals and lithium sulfinamides. The Ni⁰-catalyzed ACCR of three different types of metalloalkenyl sulfoximines, including acyclic, axially chiral and exocyclic derivatives, with sp² organolithiums and sp² and sp³ Grignard reagents has been studied. The ACCR of metalloalkenyl sulfoximines with PhLi in the presence of the Ni⁰-catalyst and precatalyst Ni(PPh₃)₂Cl₂ afforded alkenyllithiums, under inversion of configuration at the C atom and complete retention at the S atom. In a combination of experimental and DFT studies, we propose a catalytic cycle of the Ni⁰-catalyzed ACCR of lithioalkenyl sulfoximines. Computational studies reveal two distinctive pathways of the ACCR, depending on whether a phosphine or 1,5-cyclooctadiene (COD) is the ligand of the Ni atom. They rectify the underlying importance of forming the key Ni⁰-vinylidene intermediate through an indispensable electron-rich Ni⁰-center coordinated by phosphine ligands. Fundamentally, we present a mechanistic study in controlling the diastereoselectivity of the alkenyllithium formation via the key lithium sulfinamide coordinated Ni⁰-vinylidene complex, which consequently avoids an unselective formation of an alkylidene carbene Ni-complex and ultimately racemic alkenyllithium.     

SYNTHESES AND SOME PROPERTIES OF SULFOXIDES,SULFILIMINES, AMINOSULFONIUM SALTS AND SULFOXIMINES CONTAINING PYRIDINE NUCLEI

Abstract

Several 2-pyridyl sulfides (1) (e.g., methyl (1a), ethyl (1b), isopropyl (1c), benzyl (1d), 1-phenylethyl (1e), l-menthyl (If) 2-pyridyl sulfides; and bis(2-pyridylthio)methane (1g), and methyl 2-(N-oxy-pyridyl) sulfide (1h) were prepared by the usual method. Sulfoxides (2) were prepared by oxidation of the corresponding sulfides with m-chloroperbenzoic acid in good yields. A few sulfoxides were found to work as phase-transfer catalysts for some typical nucleophilic reactions in nonpolar solvents such as benzene, and in two-phase systems such as benzene-water. S-2-Pyridyl-N-(p-toluenesulfonyl) sulfilimines (3) were prepared upon treatment of sulfides with Chloramine-T. Hydrolysis of N-(p-toluenesulfonyl)-2-pyridyl-o-tolylsulfilimine (3i) with conc. sulfuric acid gave the corresponding free sulfilimine in a moderate yield. S-2-Pyridyl sulfoximines (4) were not obtained by the general method from the sulfoxides and hydrazoic acid. Alkyl-2-pyridyl sulfoximines, however, were obtained by oxidation of the free sulfilimines derived from the corresponding aminosulfonium salts (5) prepared by reaction of the sulfides with mesitylene-sulfonylhydroxylamine (MSH). These free sulfilimines and sulfoximines thus prepared were found to give adducts with a few copper salts.     

Phosphorus(III)-Nitrogen-Sulphur Compounds: Synthesis and Metal Complexes

Abstract

The preparation and X-ray structure (M=Mo) of complexes of the type M(CO)₅(Ph₂PNSO) (M=Cr,Mo) are described. These complexes are used in the synthesis of homo- and hetero-dinuclear complexes of Ph₂PNSNPPh₂. A ³¹P DNMR study of these dinuclear complexes indicates a cis, trans → trans, cis isomerization in solution. The preparation and X-ray structure (M=Cr) of the mononuclear complexes, cis-M(CO)₄(P(Ph)₂NSN(Ph)₂P), (M=Cr,Mo) are also described.     

Efficient copper-induced coupling between NH-fluoroalkylated sulfoximines and aryl iodides or bromides

A high yielding, simple, and flexible copper-based system for N-arylation of fluorinated sulfoximines is reported. Best results were achieved using copper iodide in combination with DMEDA and Cs₂CO₃ to provide a wide range of N-arylated perfluoroalkylated sulfoximines. These conditions tolerate a great number of substituents on either aromatic cycle, including heteroaromatic rings, for the N-functionalization.     

DICHLOROBIS[1,4-DIAZABICYCLO(2,2,2)OCTANE]-(TETRAHYDROBORATO)ZIRCONIUM, [Zr(BH4)2CL2(dabco)2] (ZrBDC), A NEW STABLE,EFFICIENT, AND SELECTIVE REDUCING AGENT

ABSTRACT

High yield preparation of a new stable zirconium borohydride, [Zr(BH₄)₂Cl₂(dabco)₂] is described and its application for the selective and efficient reduction of aldehydes and ketones is presented.     

Zum aminkatalysierten Abbau von Oligochlorsilan mit HCl

Tetrakis(trichlorosilyl)silan (neo-Si₅Cl₁₂) is cleaved in an amine catalysed reaction by HCl in benzene solution to tris(trichlorosilyl)silan HSi(SiCl₃)₃ (1). The amine catalysed cleavage of1 with different amines and solvents is investigated. A new method for preparation of pentachlorodisilane HSi₂Cl₅ is described and a reaction mechanism for the cleavage is postulated.

     

Synthesis of 4‐(Indol‐1‐yl)butanals via Rhodium‐Catalyzed Hydroformylation of 1‐Allylindoles

The rhodium‐catalyzed hydroformylation of new 1‐(β‐methallyl) indoles 1a–e carried out with Rh₄ (CO)₁₂ as the catalyst precursor, at 100 atm total pressure and 100°C, produces the 4-(indol‐1‐yl)‐3‐methylbutanals 2a–e as the sole products in high yields. The synthesized 4‐indolylbutanals are stable under the adopted conditions and are isolated and characterized here for the first time. The preparation of the starting 1‐allylindoles is described too.     

Regioselective alkylation of the lower rim of p-tert-butylthiacalix[4]arene with N-(p-nitrophenyl)-α-bromoacetamide

The preparation of partially substituted thiacalix[4]arenes 2–6 has been accomplished by conducting the reaction of the thiacalixarene 1 with N-(p-nitrophenyl)-α-bromoacetamide in acetone or acetonitrile in the presence of M₂CO₃ (M = Na, K and Cs). The influence of the reaction conditions (temperature, time, solvent, ratio of the reagents and the nature of the alkali metal carbonate) on regio- and stereoselectivity of this reaction is described.     

Metal-free imination of sulfoxides and sulfides

Using a nitrogen transfer agent obtained in situ by mixing of NsNH₂ and PhI(OAc)₂, various N-nosyl sulfoximines and N-nosyl sulfilimines have been prepared under metal-free conditions starting from the corresponding sulfoxides and sulfides, respectively.     

RINGCLOSURE REACTIONS WITH CARBON SUBSULFIDE

Abstract

Carbon suboxide has been used frequently in organic synthesis,¹ especially in the synthesis of heterocyclic compounds not obtainable by other routes. Although carbon subsulfide is known for more than 80 years, until recently only a few simple derivatives such as dithiomalonamides were prepared. The reason for this situation arises from the difficulties encountered in the preparation of C₃S₂. We have recently described a modification of the known preparation procedures, taking advantage of commercially available glassware (Quickfitt)².     

One pot synthesis of the dinucleoside phosphonate GpCH2U

Summary The preparation of the dinucleoside phosphonate GpCH₂U, starting from the isosteric phosphonate analogue of uridine (3) and the guanosine derivative5 is described.

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Eintopfsynthese des Dinucleosidphosphonats GpCH₂U

Zusammenfassung Die Herstellung des Dinucleosidphosphonats GpCH₂U aus dem isosteren Phosphonatanalogen von Uridin (3) und dem Guanosinderivat5 wird beschrieben.

     

Synthesis of New Cα,α-Diarylaminomethylphosphonic Acids and their Esters

Abstract

A procedure for the preparation of N-protected 1 or unprotected C_a,a-disubstituted (diarylaminomethyl)-phosphonic acids and their esters is reported.¹ This method is a generalisation of the Kabachnik-Fields method described in the literature.²     

Practical Preparation and Reactivity of Valuable Functionalized Cyclic α,α'-Ketodiesters

A study including some aspect of the reactivity and the preparation of cyclic ketodiesters from the condensation of dimethyl 3-oxoglutarate 1 with various bishalomethyl derivatives 2—6 using K₂CO₃ in THF is described.     

Oxidationsreaktionen am 1-(3,3-Dimethyl-5-norbornen-2-yl)ethanon und ein neuer Zugang zuendo-konfigurierten Isocamphanderivaten

The synthesis of some new compounds with the isocamphane skeleton obtained by oxidation reactions on the bicyclic ketone3 and its derivatives is described. Some possible routes to theendo-configurated camphenilanic acid (2) have been explored which yet have to be improved to furnish better yields. Separation of mixtures of the acids1 and2 failed. Carboxylation of camphenilone yielded only theexo-configurated isocamphenilanic acid (1).2, however, an important starting material for the preparation ofendo-configurated isocamphane derivatives, can be obtained easily with high yields and sterically pure by oxidation of camphene with H₂O₂/HCOOH. Thus a cheap, one-step method for the preparation of pure2 even in larger quantities is introduced.

Auszugsweise vorgetragen auf der 3. Wissenschaftlichen Tagung der Österreichischen Pharmazeutischen Gesellschaft am 18. Oktober 1982 in Innsbruck.     

SULFOXIMINES

Abstract

This review of sulfoximines is not intended to be an in-depth, detailed review but rather an overview of a relatively new class of reactive, interesting compounds. Topics selected for discussion reflect both the authors interests as well as the importance of the subjects.     

Transfer of Electrophilic NH Using Convenient Sources of Ammonia: Direct Synthesis of NH Sulfoximines from Sulfoxides

A new system for NH transfer is developed for the preparation of sulfoximines, which are emerging as valuable motifs for drug discovery. The protocol employs readily available sources of nitrogen without the requirement for either preactivation or for metal catalysts. Mixing ammonium salts with diacetoxyiodobenzene directly converts sulfoxides into sulfoximines. This report describes the first example of using of ammonia sources with diacetoxyiodobenzene to generate an electrophilic nitrogen center. Control and mechanistic studies suggest a short‐lived electrophilic intermediate, which is likely to be PhINH or PhIN⁺.     

One Pot Synthesis of Bisphosphonate Esters: A Way to Synthesize Tetraphosphonate Esters

Abstract

Several methods for the preparation of symmetrical bisphosphonates of general type (RO)₂P(O)(R′OH)P(O)(OR)₂, have been developed, and investigated for their pharmacological. Pharmacological screening of these bisphosphonates have shown that these compounds have potent cardiovascular activity and are. potentialy useful in the treatment of hypertension. In this work we described of new method “one pot” for the synthesis of hydroxy bis and tetra phosphonates (I, II, III and IV).     

Fe（C5H4-CH2-Trp-OMe）2的合成、晶体结构及金属离子识别性能

摘要： 以优化的两步一锅反应法合成了生物金属有机化合物Fe（C₅H₄-CH₂-Trp-OMe）₂（FcL）,通过NMR、HRMS及IR等对其结构进行了表征,利用X射线单晶衍射测定了分子结构。循环伏安法研究表明FcL在0.00~0.90 V电位范围内,给出一稳定的、形态良好的氧化还原峰,这归于化合物中Fc/Fc⁺电对的氧化还原过程。电化学金属离子识别研究显示FcL在过渡金属离子Zn²⁺和Cu²⁺的存在下,导致了配体Fc/Fc⁺式量电位的显著阳极移动,其△E^0''对Zn²⁺和Cu²⁺分别为342和335 mV,表明了FcL对Zn²⁺和Cu²⁺具有良好的识别能力。     

Facile,Highly Stereoselective Synthesis of Cyclopropyl Benzoimidazoles via Cyclopropanation of Olefin with Arsonium Ylides

A facile and highly stereoselective methodology for the preparation of highly functionalized trans-1,2-cyclopropanes containing benzoimidazolyl, cyano, aryl, and carbonyl groups 3 is described. Arsonium bromides 2 reacted with electron-deficient olefins 1 in the presence of KF·2H₂O to provide 3 exclusively with high stereoselectivity in moderate to good yields.