Photosonosynthesis of 1,2,4-tris(methylthio)-3-H-hexafluoro-n-butane

The preparation of neat 1,2,4-tris(methylthio)-3-H-hexafluoro-n-butane is described. The mechanism, which involves the elimination of hydrogen fluoride with the subsequent isomerization in forming the $\text{cis}$- and $\text{trans-}$ 1,2,4-tris(methylthio)hexafluoro-l-butene, is discussed. This study also supports the presence of methanethiol as an intermediate during the photosonoreaction of bis(methylthio)hexafluoro-2-butene with an excess of methyl disulfide.     

Chiral synthesis of statine

Statine ($\text{8a}$) has been obtained in high enantiomeric purity as its N-Boc-ethyl ester ($\text{8b}$) in a chiral synthesis. The sequence involves the enantio- and erythro-selective aldol condensation of N-Boc-L-leucinal ($\text{5}$) with (S)-4-(1-methylethyl)-3-[(methylthio)acetyl]-2-oxazolidinone ($\text{1}$) via the boron enolate, followed by desulfurization and saponification in ethanol, according to the methodology of Evans.     

Highly fluorinated heterocycles. Part XII. Some reactions of the heptafluoro-p-dioxanyl anion.

2$\text{H}$-heptafluoro-$\text{p}$-dioxan has been lithiated using methyl lithium in ether and thence converted to heptafluoro-p-dioxan-2-carboxylic acid (characterised as its anilinium and S-benzylthiouronium salts and methyl ester), 2-(heptafluoro-$\text{p}$-dioxanyl)propan-2-ol [dehydrated to 2-(heptafluoro-$\text{p}$-dioxanyl)propene], heptafluoro-$\text{p}$-dioxanyltrimethylsilane, and heptafluoro-2-iodo-$\text{p}$-dioxan. This last was converted to its Grignard reagent, and to bis(heptafluoro-$\text{p}$-dioxanyl)mercury, and was copper-coupled to trans-1-chloro-2-iodoethylene.Decomposition of heptafluoro-$\text{p}$-dioxanyl-lithium gave hexafluoro-$\text{p}$-dioxene. 2$\text{H}$-heptafluoro-$\text{p}$-dioxan, with KOH and formaldehyde, afforded hexafluoro-$\text{p}$-dioxanylmethanol.     

Bis(triphenylphosphine)copper (I) tetrahydroborate in the reduction of P-toluenesulphonylhydrazones and 2,4,6-triisopropylbenzenesulphonyl hydrazones (trisyl hdyrazones) to alkanes

Saturated ketones and aldehydes are converted via their $\text{p}$-toluenesulphonyl hydrazones to the corresponding alkanes by treatment with bis(triphenylphosphine) copper (I) tetrahydroborate; trisylhydrazones give moderate yields of alkanes at room temperature on treatment with bis(triphenylphosphine)copper (I) tetrahydroborate.     

Synthesis,structure, and reactions of thiocarbonic acid derivatives new pentathiodipercarbonates, (RSS)2 CS, α,α,α-tris(disulfides), and the first α,α,α-tris(trisulfide)

Novel bis(perhaloalkyl) pentathiodipercarbonates $\text{5b-d}$ have been synthesized by reaction of sulfenyl chlorides with metal trithiocarbonates, and the heptathio analog $\text{21a}$ was prepared similarly. Lenthionine $\text{19}$ is the main product when diiodomethane is treated with sodium tetrathiopercarbonate. A rearrangement of bis(alkyldithio)chloromethanesulfenyl chlorides $\text{22}$ to alkyldithio) (alkyltrithio)dichloromethanes $\text{24}$ has been observed. Additions of sulfenyl chlorides and of thiosulfenyl chlorides to the thiocarbonyl compounds $\text{5}$ and $\text{21a}$ were achieved in acetonitrile. The structures of the first crystalline pentathiodipercarbonate $\text{5a}$ and α,α,α-tris(disulfide) $\text{29a}$, and of the first reported α,α,α-tris(trisulfide)$\text{31a}$ have been determined by X-ray crystallography.     

Isolation of a crystalline thiete and its ‘open’ isomer; Photoproducts of xanthenethione and bis(tert-butylthio)ethyne

Irradiation of xanthenethione $\text{1}$ with bis(tert-butylthio)ethyne $\text{2}$ yielded both the expected α,β-unsaturated dithioester $\text{4b}$ and surprisingly its proposed intermediate thiete $\text{3b}$ as crystalline compounds. In solution an equilibrium between both compounds has been observed.     

‘Lepidopterene’ and its dimethylderivative ; Formation of three σ bonds through formal 5πs + 5πs thermal cycloaddition

In contrast to previous reports, the colourless products obtained in the preparation of 1,2 bis (9′-anthranyl) ethanes are not the photoisomers $\text{4}$ but new polycyclic compounds of type $\text{3}$ which we propose to call lepidopterenes, on account of their suggestive shape.     

Generation and reactivity of bis(2,6-diethylphenyl)germanium(II)

The title intermediate ($\text{3a}$) is produced on photolysis of hexakis(2,6-diethyl-phenyl)cyclotrigermane ($\text{1}$) or bis(2,6-diethylphenyl)bis(trimethylsilyl)germane ($\text{4}$) as evidenced by trapping experiments, and thermally dimerizes to tetrakis(2,6-diethyl-phenyl)digermene ($\text{2a}$). Diarylgermylenes such as $\text{3a}$ do not form stable triethylamine adducts (e.g. $\text{5a}$) as has been previously reported.     

Highly efficient method for oxidation of alcohol with tert -butyl hydroperoxide catalyzed by diaryl diselenide

In the presence of a catalytic amount of diphenyl diselenide (0.1–0.2 eq) $\text{tert}$-butyl hydroperoxide oxidized benzylic and primary allylic alcohols in high yields. Saturated alcohols were alo cleanly oxidized by the use of bis(2,4,6-trimethylphenyl) diselenide.     

A very crowded molecule: formation of bis(2,4,6-tri-t-butylphenyl)phosphinic chloride

Reaction of 2,4,6-ri-t-butylphenyllithium with phosphoryl trichloride gave a very crowded compound, bis(2,4,6-tri-t-butylphenyl)phosphinic chloride ($\text{1}$), and 2,4,6-tri-t-butylchlorobenzene ($\text{3}$), while the reaction with thiophosphoryl trichloride afforded $\text{3}$.     

Perrottetins E,F, and G from Radula perrottetii (liverwort)--isolation,structure determination,and synthesis of perrottetin e

Perrottetin E, a cytotoxic bis(bibenzyl) ether, was isolated from $\text{Radula perrottetii}$ and its structure determined by spectroscopic methods and total synthesis. Perrottetins F and G were also isolated from the same source and fully characterized.     

Bis-thallium(I) porphyrin complexes

Treatment of octaethylporphyrin ($\text{1}$) or tetraphenylporphyrin ($\text{2}$) with more than two equiv of thallium(I) ethoxide gives the corresponding stable bis[thallium(I)] porphyrin complexes ($\text{5}$) and ($\text{6}$), respectively; these thallium(I) porphyrins are shown to have very different chemical and spectroscopic properties than do the corresponding thallium(III) porphyrin complexes.     

X-ray molecular structure of the 1:1 adduct of [FeH(CO)4]− and dimethyl acetylenedicarboxylate. η3-[trans-2,3-bis(methoxycarbonyl)acryloyl]tricarbonylferrate

The crystal structure of a bis(triphenylphosphine)iminium salt of the 1:1 adduct of [FeH(CO)₄]^? and dimethyl acetylenecarboxylate has been determined from three-dimensional X-ray data collected by the counter method. Single crystals belong to the triclinic space space group P$\text{1}$, with two units of [C₃₆H₃₀NP₂]⁺[C₁₀H₇FeO₈]^? in a cell of dimensions: $\text{a}$ = 13.918(2), $\text{b}$ = 15.669(5), $\text{c}$ = 9.909(2) Å, $\text{α}$ = 91.22(3), $\text{β}$ = 94.83(2), and $\text{γ}$ = 77.62(2)°. The structure was refined to a conventional $\text{R}$ of 0.068 for 5373 observed

reflections. The resulting structure indicates that the complex anion is η³-[$\text{trans}$-2,3-bis(methoxycarbonyl)acryloyl]tricarbonylferrate, the coordination around the iron atom being described as a considerably distorted trigonal bipyramid. A comparison of the present structure with the structures of related complexes suggests that the η³-acryloyl portion is best represented as an intermediate of (η³-allyl) with the oxygen atom and (η²-olefin + η¹-acyl). The short Fe-C(acyl) length of 1.897(5) Å implies an enhanced back-donation of electrons from the iron atom to the acyl group.     

α-Phenylselenenylation d'aldehydes - synthese simple d'α-cetoaldehydes a fonction cetone protegee

Morpholinophenylselenenamide $\text{2}$ add to β-phenylselenoenamines $\text{1a}$ and yield β,β-bis(phenylseleno) enamines $\text{4}$. These compound undergo hydrolysis to form bis(phenylseleno) ethanal $\text{5a}$. Also, $\text{2}$ react with enolic aldehydes to give α-phenylselenoaldehydes $\text{3}$. This reaction allow a “one step” synthesis of cetoselenoacetals $\text{5}$ of α-cetoaldehydes with good yields.     

Preparation and reactivity of mesoionic 1,2,4-triazolo-[4,3-b]-1,2,4-triazole derivatives

A number of mesoionic compounds (2) derivatives of the 1,2,4-triazolo[4,3-$\text{b}$]-1,2,4-triazole ring system have been prepared from 4-amino-1 -methyl -3,5-bis(methylthio)- 1,2,4-triazolium cation and aryl isothiocyanates. Compounds ((2) react with methyl iodide to give the methiodides ((3) which undergo ring opening to the monocyclic compounds ((4) through sulfur extrusion under thermal conditions. Methiodides ((3) by sequential treatment with malononitriIe and hydrochloric acid lead to the pyrazolo[5,1-$\text{c}$]-1,2,4-triazole (6).     

Crotylzirconium derivatives as a new reagent for the threo selective synthesis of β-methylhomoallyl alcohols

Crotylzirconium derivatives, prepared from the reaction of crotylmagnesium chloride or crotyllithium with bis (cyclopentadienyl) zirconium dichloride, undergo a rapid reaction with aldehydes to afford the threo product predominantly. The ratio of Cram/anti-Cram product via this reagent is ca. $\text{75}\text{25}$ ~ $\text{60}\text{40}$.     

Selective removal of ortho halogens by a diorganolanthanoid

Reaction of halogenobenzoic acids with bis(pentafluorophenyl)ytterbium(II) in tetrahydrofuran results in selective removal of $\text{ortho}$ halogen substituents.     

Mercury mediated synthesis of bis(carboxy)iodobenzenes

Iodobenzene dibenzoates and acetoxylates can be conveniently prepared from iodobenzene dichloride and the corresponding mercuric carboxylate generated $\text{in}$ $\text{situ}$. Especially noteworthy is the high yield preparation of bis(trifluoro-acetoxy) iodobenzene.     

Synthesis of mesoionic xanthine nucleosides

The synthesis of the first examples of Class II mesoionic xanthine nucleosides is described. Tri-O-acetylribofuranosylaminothiazole is cyclized by condensation with bis (2,4,6-tri-chlorophenyl) malonate and the resultant product is de-protected to yield $\text{anhydro}$ (8-β-$\text{D}$-ribofuranosyl-5-hydroxy-7-oxothiazolo [3,2-a] pyrimidinium hydroxide); the glucosyl derivative is prepared in a similar manner.     

Synthesis of di-t-alkylamines

Di-$\text{t}$-alkylamines can be synthesized efficiently by a three-step process: (1) oxidation of a $\text{t}$-alkylamine to a $\text{t}$-alkylnitroso compound with peracetic acid in ethyl acetate (2) conversion of the $\text{t}$-alkylnitroso compound to a tri-$\text{t}$-alkylhydroxylamine by successive trapping of two $\text{t}$-butyl radicals and (3) sodium naphthalide reduction to the di-$\text{t}$-alkylamine.