1,2-Dialkoxycarbonylhydrazine derivatives of pyrroles and indolizines. A new synthesis of cycl[3.2.2]azines

The reaction of pyrroles $\text{1}$ with diisopropyl azodicarboxylate $\text{2}$ yields 2- and 2,5-substituted derivatives. 3- and 1,3-substituted indolizines $\text{5}$ and $\text{6}$ are formed by the same route. Cycl[3.2.2]azines $\text{7}$ have been obtained from $\text{5}$ and $\text{6}$ with dimethyl acetylenedicarboxylate.     

3-methylthio-1,2-dithiolylium salts : Reaction with 4-hydroxy-6-methyl-2H-pyran-2-one and 4-hydroxycoumarin

The reaction of 4- and 5-aryl-3-methylthio-1,2-dithiolylium iodides with 4-hydroxy-6-methyl-2$\text{H}$-pyran-2-one and 4-hydroxycoumarin has been studied. 4-Substituted salts yielded 3-aryl-7-methyl-2-thioxo-2$\text{H}$,5$\text{H}$-pyrano [3,2-c]pyran-5-ones and 3-aryl-2-thioxo-2H,5H-pyrano[3,2-c]benzo[e]pyran-5-ones, respectively, whereas 5-substituted salts gave rise to 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-6-methyl-2$\text{H}$-pyran-2,4-diones and 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-2$\text{H}$-benzo [b]-pyran-2,4-diones.     

IPSO-substitutions. Reactions of 3-substituted indoles with benzoylperoxide

3-substituted indoles with benzoylperoxide led to the 3-benzoyloxy derivative. The react$\text{i}$on is discussed in terms of homolytic $\text{ipso}$-substitution.     

Organometallics in organic synthesis:tricarbonyl-(3-methoxycyclohexa-2,4-dien-1-yl)-iron(1+). A synthetic equivalent of the C-5 cation of cyclohexenone.

Tricarbonyl-(3-methoxycyclohexa-2,4-dien-1-yl)-iron(1+) PF₆(1-) $\text{2}$ reacts with a variety of nucleophiles to give 5-substituted cyclohex-2-enones. $\text{2}$ is shown to be a useful precursor for a convergent synthesis of 5-substituted cyclohex-2-enones and to be synthetically equivalent to the 5-cyclohex-2-enone cation $\text{1}$.     

Diborane as a reducing agent - VI the novel reduction of indole-1-carboxaldehydes to 1-methyl- indoles,di(indolyimethyl) ethers and indolylmethyl indolines

Reduction of the indole-1-carboxaldehydes ($\text{1a}$-$\text{1f}$) with borane /THF gives the 1-methylindoles ($\text{4}$) in 42-91-% yields together with the di(indolylmethyl)ethers ($\text{8}$), the indolyl-methyl indolines ($\text{7}$), the unsymmetric ether($\text{10}$) and the indolenine ($\text{11}$) as the minor products, except $\text{7a}$. This appears to be the first report on the formation of symmetric ethers in the borane/THF reduction of an oxygen function. The formation of $\text{7a}$ and $\text{7b}$ from $\text{1a}$ and $\text{1b}$ implies that electrophilic substitution takes place primarily at position 3 of 3-substituted indoles, $\text{1c - 1f}$ did not form the corresponding $\text{7}$ probably because of steric hindrance. These results are discussed in relation to the mechanisms of borane/THF reduction, origin of the different products and electrophilic substitution in 3-substituted indoles.     

Elimination reactions of 1,2-dihalo-2,3,3-trifluorocyclobutanes

Elimination reactions on isomeric mixtures of $\text{cis}$ and $\text{trans}$ 1,2-dihalo-2,3,3-trifluorocyclobutanes are reported. In zinc-promoted dehalogenations a steady decrease in the relative amount of the $\text{trans}$ isomers compared to the $\text{cis}$ isomers occured, with 2,3,3-trifluorocyclobutene as the sole product. The $\text{cis}$ isomers reacted at a faster rate in potassium hydroxide induced eliminations to yield a slight predominance of 1-halo-2,3,3-trifluorocyclobutenes over 3-halo-3,4,4-trifluorocyclobutenes. However, with triethylamine as the inducing base, an increased rate of elimination from the $\text{trans}$ isomers was noted along with almost exclusive formation of 3-halo-3,4,4-trifluorocyclobutenes.     

Spiroadamantyl stabilization of sulfur-substituted 1,2-dioxetanes

With the help of spiroadamantyl substitution, the first sulfur-substituted 1,2-dioxetanes $\text{9}$ and $\text{10}$, respectively derived from thiophenylmethyleneadamantane ($\text{7}$) and 2-adamntylidene-1, 3-dithian ($\text{8}$) were prepared via singlet oxygenation and detected by NMR.     

Syntheses of 3-substituted furans via lithium di(3-furyl)cuprate—the application of lithium di(3-furyl)cuprate to the total synthesis of dendrolasin

One step syntheses of 3-substituted furans by the reactions of a new reagent, lithium di(3-furyl)cuprate $\text{1}$, with various substrates and the application of $\text{1}$ to a total synthesis of dendrolasin are described.     

New methods and reagents in organic synthesis, 24. A new synthesis of prumycin as an application of the direct c-acylation using diphenyl phosphorazidate (DPPA)

The 5-substituted 4-methoxycarbonyloxazole $\text{5}$ derived from L-serine derivative $\text{3}$ using diphenyl phosphorazidate (DPPA) has been converted to a 2,4-diaminosugar antibiotic, prumycin.     

Novel adducts of sulfides and 4-substituted 1,2,4-triazoline-3,5-diones ( TAD ) A similarity of TAD and singlet oxygen( 1O2 )

The 4-substituted 1,2,4-triazoline-3,5-diones( $\text{2}$ ) afford with sulfides( $\text{1}$ ) having acidic α-hydrogens the 1,4-disubstituted urazoles( $\text{3}$ ). Reactivity of the triazolinedione shows similarity in possible reaction modes with that of singlet oxygen.     

Electron exchange chemiluminescence from a sterically stabilized cyclobutadiene-1,2-dioxetane

The rather stable 1,2-dioxetanes ($\text{2}$) and ($\text{3}$), derived from the sterically stabilized cyclobutadiene ($\text{1}$), exhibit distinct enhanced chemiluminescence behavior, namely energy transfer chemiluminescence (ETC) for ($\text{2}$) and electron exchange chemiluminescence (EEC) for ($\text{3}$).     

Stereoselectivity in cycloaddition of phenylglyoxylonitrile oxide to 7-substituted norbornadienes and 8-substituted 2-azabicyclo[3.2.1]oct-3,6-dienes

The cycloaddition of phenylglyoxylonitrile oxide to the 7-substituted norbornadienes $\text{1}$a-c gives predominantly the endo isomers, but that to the 8-substituted 2-azabicyclo[3.2.1]oct-3,6-dienes $\text{2}$a,b the exo isomers.     

1,4-Addition of dichlorocarbene to 1,2-bismethylenecycloheptane

The reaction of dichlorocarbene with 1,2-bismethylenecycloheptane $\text{3}$ yields, besides the 1,2-addition product $\text{4b}$, the 1,4-addition product $\text{6b}$ in a ration 99:1.     

Photochemical studies. Irradiation induced transformations of 1,2-dihydrophthalides

The photochemical behavior of $\text{cis}$-1,2-dihydrophthalide ($\text{1}$) and its 1,2-trimethylene derivative ($\text{4}$) was studied. Besides bicyclo[2.2.0]hexene formation in both cases, ($\text{1}$) transforms into its $\text{trans}$ isomer ($\text{3}$) whereas ($\text{4}$) undergoes a 1,2-shift to ($\text{7}$).     

A new stereoselective synthesis of 2-subsdtituted 1,3-bis(trimethylsilyl)propene derivatives and their conversion to cyclopentane and cyclohexane derivatives

Ester $\text{2}$ on treatment with sodium salt of sulfone or sulfoxide afforded 2-substituted 1,3-bis(trimethylsily)propene $\text{3}$ in good yield, from which cyclopentane and cyclohexane derivatives bearing a trimethylsilyl group in the molecules were synthesized.     

Asymmetric synthesis of 2-substituted cycloalkanecarboxaldehydes

The 1,4-addition of Grignard reagents to chiral α,β-unsaturated cyclic aldimines ($\text{3}$), prepared from the corresponding cycloalkenecarboxaldehydes ($\text{1}$) and optically active α-amino acid tert-butyl esters ($\text{2}$, was found to give, after hydrolysis, trans-2-substituted cycloalkanecarboxaldehydes ($\text{5}$) in reasonably high enantiomeric purities.     

Facile synthesis of 4-substituted pyridines using grignard reagents

N-t-Butyldimethylsilylpyridinium triflate $\text{2}$ reacted with Grignard reagents at 4-position with almost complete regioselectivity ($\text{>}$99%) to afford the corresponding 1,4-dihydropyridine derivatives ($\text{3}$), which are easily oxidized by oxygen to give 4-substituted pyridines ($\text{4}$: 58 – 70%).     

Enantiocontrolled synthesis of (S)-3-substituted cycloalkanones from (s)-2-(p-tolylsulfinyl)-2-cycloalkenones and diorganomagnesium reagents.

By appropriate choice of reaction conditions, the $\text{same}$ enantiomerically pure ($\text{S}$)-(+)-2-($\text{p}$-tolylsulfinyl)cycloalkenone can be converted into $\text{either}$ an ($\text{R}$)-or an ($\text{S}$)-3-substituted cycloalkanone in good to excellent enantiomeric purity.     

A novel synthesis of 3-cyanoindoles and a new route to indole-3-carboxylic acid derivatives

2-Alkyl-3-cyanoindoles are obtained when 1-alkylmethyl-2-chloro-(or 2-phenylsulfonyl)-3-phenylsulfonylindoles are reacted with excess azide ion (90°/DMF). The reaction is considered to occur by a fragmentation recombination process in which the Schiff's base $\text{12}$ is of central importance. This proposal is supported by the formation of 2-substituted indole-3-carboxylates $\text{17}$ from aldehydes and the α-phenylsulfonyl-$\text{o}$-aminophenylacetic acid ester derivative $\text{16}$.     

Addition conjuguee d'equivalents d'acyles aux cyclohexen-2 ones et a la Δ1(9) octalone-2: Synthese de dicetones 1–4.

The synthesis of 3-acetylcyclohexanones $\text{11}$, $\text{12}$, $\text{13}$ has been realized by conjugate addition of lithiated cyanohydrin ether $\text{1a}$ to 2-cyclohexenones $\text{2}$, $\text{3}$, $\text{4}$ in THF-HMPA, even if 3-substituted. 3-benzoylcyclohexanones $\text{14}$, $\text{15}$, $\text{16}$ are obtained from $\text{1b}$ and $\text{2}$, $\text{3}$, $\text{4}$ in THF with excellent yields.