A simple synthesis of 3-substituted furans. The preparations of dendrolasin,perillene and congeners

The Grignard reagent $\text{7}$, derived from 3-chloromethyl furan, reacts with various alkyl- and allylic halides, in the presence of Li₂CuCl₄, to provide high yields of 3-substituted furans.     

Über reaktionen mit aluminiumalkylen: XVII. Spektroskopische untersuchungen von komplexen aus butanoliden und äthylaluminium-verbindungen

Three different types of butanolide complexes with Et_nAlCl_3?n in the molar ratios $\text{1}\text{1}$ and $\text{1}\text{2}$ have been investigated by IR with ^1M NMR spectroscopy. The butanolides form $\text{1}\text{1}$ and $\text{1}\text{2}$ complexes with ethylaluminium halides, but with triethylaluminium only $\text{1}\text{1}$ complexes are formed. The complexes are intermediates in the cleavage of butanolides.     

Reaction of n-alkylthiazolium halides,including thiamine,with superoxide ion. Chemistry and biological implications.

$\text{N}$-alkylthiazolium halides are transformed by KO₂ into the corresponding thiazolin-2-ones and thiazolin-2-thiones; the same reactions occur with thiamine, whose thiazolin-2-one pyrophosphate has been reported to be a strong inhibitor of pyruvic dehydrogenase.     

The crystal structure of strontium tetraiododiargentate octahydrate,SrAg2I4 · 8H2O

Crystals of strontium tetraiododiargentate octahydrate, SrAg₂I₄ · 8H₂O belong to the tetragonal space group I422(D⁹₄), with a = 12.86 ± 0.03, c = 5.56 ± 0.02Å, and Z = 2. The structure may be described as having, in one-to-one ratio, columns formed by [Sr(H₂O)₈]²⁺ entities centered at (0, 0) and ($\text{1}\text{2}\text{,}\text{1}\text{2}$) and chains of edge-sharing AgI₄ tetrahedra centered at ($\text{1}\text{2}$, 0) and (0, $\text{1}\text{2}$), the chains being linked to each other through water molecules by hydrogen bonding and through van der Waals forces between iodide ions. The crystals are obtained from a saturated aqueous solution of SrI₂ which is then saturated with AgI; dilution of this solution or addition of water to the crystals precipitates β-AgI. This demonstrates the ease with which the three-dimensional corner-sharing tetrahedra of the β-AgI transform to the edge-sharing chain arrangement of tetrahedra and vice versa. It is probable that the saturated solution itself contains [Sr(H₂O)₈]²⁺ and AgI₄-chain entities.Anhydrous compounds of strontium and barium halides with silver and copper halides appear to be unattainable at atmospheric pressure. It is speculated that this is associated with the particular coordination requirements of the alkaline earth ions.     

Anionic tricarbonyl derivatives of molybdenum and tungsten and their reactions with allyl halides

A series of carbonylmetallate anions $\text{fac}$-[MX(CO)₃L₂]^?, where M = Mo or W, X = Cl, Br or I and L₂ = 1,10-phenanthroline(phen) or 2,2′-bipyridine(bipy) have been prepared from the corresponding $\text{cis}$-M(CO)₄L₂ complexes. No evidence of $\text{fac}$-to $\text{mer}$-isomerisation was evident on dissolution, although in MeCN solvolysis occurred with the formation of $\text{fac}$-M(CO)₃L₂(MeCN). Reaction of the anions with various allyl halides resulted in high yields of η³-allyl complexes [MX(CO)₂(η³-RC₃H₄)L₂]. The significance of these observations for the mechanism of the allyl oxidative-addition reaction are discussed.     

The interaction of an osmium-carbon triple bond with copper(I), silver(I) and gold(I) to give mixed dimetallocyclopropene species and the structures of Os(AgCl) (CR) Cl(CO) (PPh3)2

The osmium carbyne complex, Os(CR)Cl(CO)(PPh₃)₂, (R  p-tolyl) reacts with Group I halides to form the mixed dimetallocyclopropene species, $\text{Os(Cul)(C}$R)Cl(CO)(PPh₃)₂, $\text{Os(AgCl)(C}$R)Cl(CO)(PPh₃)₂, $\text{Os(AuCl)(C}$R)Cl(CO)(PPh₃)₂, and [$\text{Os[Ag(OClO}{}_3\text{)](C}$R)Cl(CO)(MeCN)(PPh₃)₂] ClO₄ X-ray crystal structure determination of $\text{Os(AgCl)(C}$R)Cl(CO)(PPh₃)₂ confirms the presence of a three-membered ring and the structure can be viewed as the “acetylene-like” interaction of an osmium—carbon triple bond with AgCl. In acid solution AgCl is precipitated and an alkylidene complex results from proton addition to the carbyne ligand.     

Intramolecular cyclizations of α-ketoimidoyl halides derived from organic isonitriles. An expedient approach to the synthesis of 1-acyl-3,4-dihydroisoquinolines

Dihydroisoquinolines are formed in high yield $\text{via}$ the cyclization of α-ketoimidoyl halides prepared by the reaction of phenethyl isocyanides with acyl halides.     

Dimetalated tertiary succinamides. Synthesis of several classes of lignans including the mammalian urinary lignas enterolactone and enterodiol

Reaction of dimetalated succinamides with benzyl halides and aromatic aldehydes provides short routes to diverse lignan natural products $\text{2}$, $\text{3}$, and $\text{4a}$, including the human urinary metabolites ($\text{3d}$) and ($\text{2e}$).     

Organomercury compounds XX Reactions of lithium polyfluorobenzenesulphinates with mercuric salts

The lithium polyfluorobenzenesulphinates, Li O₂SR (R = C₆F₅, $\text{p}$-HC₆F₄, $\text{m}$-HC₆F₄, or $\text{o}$-HC₆F₄), and the dilithium tetrafluorobenzenedisulphinates, $\text{p}$- and $\text{o}$-(LiO₂S)₂C₆F₄, have been prepared by reaction of the appropriate polyfluoroaryllithium compounds with sulphur dioxide. All compounds were isolated as hydrates and gave the corresponding $\text{S}$-benzylthiouronium salts on treatment with $\text{S}$-benzylthiouronium chloride. From reactions of the lithium sulphinates with suitable mercuric salts in water, generally at room temperature, the derivatives RHgX (R = C₆F₅, X = Cl, Br, CH₃CO₂, or PhSO₂; R = $\text{p}$-HC₆F₄, X = Cl, Br, or CH₃CO₂; R = $\text{m}$-HC₆F₄, X = Cl or Br; R = $\text{o}$-HC₆F₄, X = Cl), $\text{p}$-(XHg)₂C₆F₄ (X = Cl, Br, or CH₃CO₂), and $\text{o}$-(XHg)₂C₆X₄ (X = Cl or Br) have been prepared. Similarly, the bispolyfluorophenylmercurials R₂Hg (R = C₆F₅, $\text{p}$-HC₆F₄, or $\text{m}$-HC₆F₄) have been prepared from the corresponding lithium sulphinates and either mercuric salts or polyfluorophenylmercuric halides in aqueous $\text{t}$-butanol. A possible mechanism for the sulphur dioxide elimination reactions is discussed.     

Photochemistry of organic halides: Some interesting features of the photobehaviour of vinyl halides and vinylidine dihalides derived from camphene

A study of the photochemistry of vinylidine dihalides $\text{1}$ and $\text{2}$ and vinylhalides $\text{4}$ and $\text{5}$ revealed some interesting differences in their photobehaviour. This study led to uncover an important constraint in the generation of vinyl cations from certain α-unsubstituted vinyl halides such as $\text{4}$.     

Synthesis and 13C nmr characterization of some π-excessive heteropolyaromatic compounds

Several π-excessive heteropolyaromatic compounds, which contain furan and thiophen ring and are possible antifungal agents, have been synthesized in good yields according to two general methods. The first method has been used to prepare compounds possessing thiophens linked by their 2- and 5-positions, such as the ter-aryls $\text{2b}$, $\text{2d}$ and $\text{2a}$. Two precursors of these compounds have been obtained either by the Glaser reaction, or using a novel Pd-mediated reaction. The second method,which consists of the Ni-or Pd-catalyzed heteroarylation of heteroarene halides via cross-coupling with heteroaryl Grignard reagents or zinc halides,has been used to prepare the bi-aryls $\text{1a-e}$, which contain two heteroaromatic units, and the ter-aryl $\text{2c}$. Compound $\text{1e}$ has been also prepared starting from 2-(2-thienyl) furan ($\text{1c}$) by selective lithiation, followed by bromination.The ¹³C NMR signals of $\text{1a-e}$ and $\text{2a-d}$ have been assigned on the basis of the literature data and by relaxation measurements. Relaxation data have been also used to obtain qualitative informations on the conformational equilibria of the bi-aryls $\text{1a}$, $\text{1c}$ and the ter-aryls $\text{2a-d}$.     

Palladium catalysed synthesis of N and S heterocyclic esters

Palladium catalysed alkoxycarbonylation of heterocyclic halides affords a simple and versatile synthesis of both $\text{N}$ and $\text{S}$ heterocyclic esters where a range of catalysts have been studied and a method to employ inexpensive inorganic bases has been found.     

Regioselective synthesis of 4-alkylquinolines from quinoline via 1-ethoxycarbonyl-1, 2-dihydroquinoline-2-phosphonates

1-Ehtoxycarbonyl-1, 2-dihydroquinoline-2-phosphonates ($\text{3}$) were treated with n-butyllithium followed by alkyl halides to afford the corresponding 4-alkylated phosphonates ($\text{7}$) with complete regioselectivity in 67–97% yields. The phosphonates ($\text{7}$) were converted to 4-alkylquinolines ($\text{8}$) in ca. 50% yields by treatment with sodium iodide in HMPA or by alkaline hydrolysis in aqueous ethanol.     

Substitutionen und insertionen an stannylierten inethern

Stannylethynyl ethers $\text{1}$ react with acyl halides or some elemental halides under substitution of the stannyl group; the carbonyl group of ketenes insert into the single bond between the acetylenic carbon atom and the stannyl group.     

Useful synthetic reagents derived from 1-triisopropylsilylpropyne and 1,3bis-[triisopropylsilyl]propyne,direct, stereoselective synthesis of either Z or E enynes

Lithio reagents derived from 1-triisopropylsilylpropyne ($\text{1}$) and 1,3-$\text{bis}$-[triisopropylsilyl]propane ($\text{3}$) are effective for the synthesis of $\text{Z}$ or $\text{E}$ terminal enyne units (CHCHCCH) and for carboncarbon bond formation with halides, aldehydes, ketones, epoxides, and α,β-enones.     

Orientation effects in reactions of allenyl cations with styrene

Allenyl cations, generated $\text{in}$$\text{situ}$ from allenyl or alkynyl halides and Ag⁺, attack styrene at the side chain or at the aromatic nucleus. The allenyl/alkynyl product ratio is dependent on the structure of the precursor halide except for highly substituted systems.     

Cyclisierungen unter beteiligung von fluoridionen. 2. Mitteil. [1], [2]. 4.5-perfluor-1.3-dioxolane

4.5-Perfluoro-1.3-dioxolanes $\text{2}$ are available by reaction of 2(α-chloroalkoxy)perfluoro-carbonyl halides $\text{3}$ or -ketone $\text{9}$ with fluoride ions. A mechanism for the intramolecular ring- closure-reaction is proposed. Hydrogen atoms at C-2 in $\text{2}$ can be exchanged photochemically by chlorine. Starting from the 2-monochloro-derivatives $\text{16}$ the 2-monofluoro-4.5-perfluoro- 1.3-dioxolanes $\text{18}$ are formed by reaction with triethylamine- hydrofluoride.     

Alkyl additions to active olefins by tributylgermanium hydride reduction of alkyl halides

Tri($\text{n}$-butyl)germanium hydride is a superior reagent for the reductive addition of alkyl halides to active olefins.     

The reactions of 2-[(dimethylamino)methyl]phenylcopper and -lithium tetramer with cuprous and cupric halides

2-[(Dimethylamino)methyl]phenylcopper tetramer (R₄Cu₄) forms a red $\text{1}\text{1}$ complex (RCu - CuBr)_n with cuprous bromide. The $\text{1}\text{1}$ interaction of 2-[(dimethylamino)methyl]phenylcopper with cupric halides results in the formation of the dimer RR, the 2-halo-substituted benzylamine R—Halide and minor amounts of N,N-dimethylbenzylamine RH. The formation of these products can be explained on the basis of an intramolecular electron-transfer redox reaction taking place in innersphere activated complexes of the type R₄Cu₃Cu - - - X - - - Cu^IIX(Cu^IIX₂)_n-1. The course of the metathesis reaction of 2-[(dimethylamino)methyl]phenyllithium with cuprous bromide depends on the order of addition of the reactants. Reversed addition (RLi to CuBr) results in the formation of an inseparable mixture of complexes of the type (RCu)_x- (CuBr)_y. Upon addition of CuBr to RLi the uncomplexed organocopper compound R₄Cu₄ is formed.     

Vinyliodonium salts : their stereospecific synthesis and reactions as the activated vinyl halides

Vinyliodonium salts $\text{2}$ were synthesized from vinylsilanes $\text{1}$ by the reaction with iodosylbenzene and triethyloxonium tetrafluoroborate. The reaction occurs stereospecifically with retention of configuration. Vinyliodonium salts $\text{2}$ are highly effective as the activated species of vinyl iodides. Thus, a variety of substituted olefins including α-cyano and α-nitro olefins, vinyl sulfides, vinyl halides, and α,β-unsaturated esters, were prepared from $\text{2}$ under mild reaction conditions.