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.     

Réactivité des dérivés organocuivreux vis-à-vis des aldéhydes αβ-éthyléniques

Secondary lithium dialkylcuprates react with αβ-ethylenic aldehydes to give a mixture of 1,2 and 1,4 addition products. Only 1,2 addition products are obtained with allylic and acetylenic cuprates whereas homallylic, phenyl and vinylic cuprates give 1,4 addition products. The $\text{1,4}\text{1,2}$ ratio also depends on the nature of the metal in the cuprate (Mg or Li). Thus chloromagnesium dimethyl cuprate, in THF, is the most favorable compound to give the 1,4 addition product.     

The reactions of trifluoromethyl and trichloromethyl radicals with conjugated and methylene-interrupted dienes and enynes

The photochemical addition of CF₃I to buta-1,3-diene and vinylacetylene in the gas phase gave 1,4-adducts as the main products. In gas phase reactions only products derived from hydrogen abstraction were detected in the CF₃I/penta-1,3-diene system, but the 1,4-adducts again predominated in the liquid phase. CCl₃Br similarly gave a mixture of 1,2- and 1,4-adducts, the latter predominating, on photochemical reaction with penta-1,3-diene. The 1,2-adduct was the main product from the CCl₃Br/pent-1-en-4-yn reaction, but some hydrogen abstraction was observed. The preference shown by conjugated dienes to give 1,4-adducts in the $\text{trans}$- configuration is interpreted in terms of steric factors and the propensity of dienes to adopt the $\text{s}$-$\text{trans}$ conformation.     

The synthesis of highly fluorinated phthalonitrile resins and cure studies

The reactions of the potassium salts of 1,3- and 1,4-bis(2-hydroxy-hexafluoro-2-propyl) benzene $\text{1}$ and $\text{2}$ with tetrafluorophthalonitrile $\text{3}$ afforded three isomeric products in each case with reaction at the 4-position of $\text{3}$ predominating. When each mixture was submitted to the usual thermal conditions for phthalocyanine formation [1–5], the expected characteristic color change (blue or green) did not develop.Evidence was procured from our study which indicated that fluorine substituted on the phthalonitrile moieties hindered phthalocyanine formation. Instead, as an alternative reaction, some nucleophilic displacement of fluorine from the aromatic rings by the cyano substituents appeared to have occurred.     

HMPA-Mediated conjugate addition of alkyl- and phenylthioallyl anions to cyclopentenone

One equivalent of HMPA induces 1,4-addition of the title anions predominantly through the $\text{α}$-position to cyclopentenone in THF at ?78°. In THF alone irreversible addition takes place to give mixtures comprising largely $\text{α}$ and $\text{γ}$-1,2 products.     

Photocycloadditions to 3-phenyl-1,2-benzisothiazole

3-Phenyl-1,2-benzisothiazole ($\text{1}$) gave upon irradiation in the presence of ethyl vinyl ether 3-ethoxy-5-phenyl-2,3-dihydro-1,4-benzosothiazepine (II) in high yield (80%).     

Etude de l''addition des organomagnesiens satures et benzyliques aux enynes conjugues, simples et fonctionnels

Saturated and benzylic organomagnesium compounds are shown to readily undergo addition reactions with the conjugated enynes H$\text{C}\text{4}$$\text{C}\text{3}$C$\text{H}\text{2}$$\text{C}\text{1}$HCH₂R′, with R′ = alkyl, OH, OC₄H₉, NHC₂₅, N(C₂H₅)₂, by refluxing for several hours in benzene or toluene.This reaction leads to both υ-acetylenic compounds (1,2-addition) and β-allenic compounds (1,4-addition).     

The reactions of aromatic compounds with bromine trifluoride (2): Octafluoronaphthalene

The reaction of bromine trifluoride with octafluoronaphthalene has been investigated, from which was obtained decafluoro-1,2-benzocyclohexa-1,4-diene, 2-bromo-undecafluorotetralin and a mixture of dibromotetradecafluorobicylo [4,4,0] decene isomers. Dehalogenation and reduction gave decafluoro-1,2-benzocyclohexa-1,3-diene in addition to the 1,4-diene and 2$\text{H}$-undecafluorotetralin, a similar mixture being obtained from the dibromo decene. The reactions of the dienes and bromofluorotetralin with methoxide ion have also been studied.     

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 ($\text{7}$).     

Stereoselective nucleophilic addition reactions to nitro sugars

Nucleophile(s) almost exclusively added from the equatorial side of 2-nitro-β-$\text{D}$-2-enopyranoside and the axial side of 2-nitro-$\text{D}$-$\text{ribo}$-1-enitol. On the other hand, methoxide and $\text{tert}$-butyl peroxide ions approached from the equatorial side of 2-nitro-α-$\text{D}$-2-enopyranoside, whereas methanol and hydrogen peroxide ion from the axial side.     

A convenient synthesis of 6-, 7-, and 8-membered cyclic phosphodiesters

1,3-, 1,4-, and 1,5-Alkanediols are converted into the corresponding 6-, 7-, and 8- membered cyclic phosphodiesters in a two-step procedure utilizing N-(1,2-dimethylethylene-dioxyphosphoryl)imidazole ($\text{2}\text{?}$ as the sole phosphorylating reagent.     

1,2-dimagnesium derivatives of cyclopropane

cis-1,2-Dibromomagnesiocyclopropane (cis-$\text{4}$) was isolated from the reaction of both trans- and cis-1,2-dibromocyclopropane ($\text{1}$) with magnesium. The corresponding dialkylmagnesium species ($\text{7}$), an oligomer of 2-magnesabicyclobutane, was obtained from cis-$\text{4}$ by precipitation in THF; it forms a soluble complex 8 with HgBr₂.     

A stereoselective synthesis of β,γ-disubstituted allylic alcohols of z-configuration

Reaction of alkyllithiums $\text{1}$ with isoprene epoxide $\text{2}$ gives β,γ-disubstituted allylic alcohols $\text{3}$ of Z-configuration. The reaction of π-lithiotricyclene as alkyllithium gives α-santalol $\text{5}$, which is one of the main constituents in East Indian sandalwood oil.     

Phthalideisoquinoline enol lactones

:(Z)-Narceine enol lactone ($\text{10}$) is thennodynamically less stable than its geometric isomer $\text{11}$, and solvolyses faster in methanol to provide keto ester $\text{9}$. In the less hindered hydrastine series, however, the order is reversed, and it is the E isoner $\text{4}$ which is less stable than the Z analog $\text{3}$ and which solvolyses faster to keto ester $\text{6}$.     

Cycloadditions des arsoles a haute temperature

At room temperature 1-phenyl-2,5-dimethylarsole $\text{1}$ gives [4+2] cycloadditions with dienophiles whereas at 160 °C it yields arsenic atoms which react with tolane to give the 1,4-diarsabicyclo[2.2.2]octatriene $\text{8}$; 1,2,5-triphenylarsole $\text{2}$ is less reactive at room temperature but isomerizes at 160°C to give the 2$\text{H}$-arsole $\text{5}$ which reacts as a diene with tolane to yield the 1-arsanorbornadiene $\text{6}$, and as a dienophile through its AsC double bond with dimethylbutadiene to give the 1-arsabicyclo[4.3.0]nonadiene $\text{7}$.     

Perhalogenmethylmercapto-heterocyclen, (VII) [1] konkurrenzreaktionen elektronenarmer,substituierter aromaten um die halogenmethylmercapto- BZW. Chlorgruppe von Cl3-nFnCSCl in starken saeuren

Electron-deficient aromatics, such as 2,5-bis(trifluoromethylmercapto)thiophene ($\text{1a}$) or (trifluoromethylmercapto)benzene ($\text{8a}$), react with F₃CSCl in the presence of F₃CSO₃ as a catalyst to give mainly 3-chloro-2,5-bis(trifluoromethylmercapto)thiophen ($\text{3a}$) and 1-chloro-4- or 2-(trifluoromethylmercapto)benzene ($\text{10}$, respectively. This reaction competes with the one expected to result in 2,3,5-tris(trifluoromethylmercapto)thiophene ($\text{2a}$) and 1,4- and 1,2-bis(trifluoromethylmercapto)benzene ($\text{9}$,$\text{9′}$), respectively. Further reactions of deactivated aromatics with Cl_3-nF_nCSCl show that the chlorine substitution is in general catalysed by strong acids. Reaction mechanisms are proposed for both Substitutions. The Cl_3-nF_nCS group in aromatics exerts a -M-effect in the case of an attack of a positive ion, e.g. H^⊕, the well-known +M-effect in the case of reactions with positively polarized molecules, e.g. CF₃S^β+Cl^β-.     

Thermal decomposition kinetics of polysilanes: Disilane,trisilane, and tetrasilane

The decomposition kinetics of disilane with added butadiene, trisilane both neat and with added butadiene, trimethylsilane or H₂, and normal and iso-tetrasilane both neat and in the presence of added butadiene are reported. Arrhenius parameters of the primary dissociation reactions are determined: A-factors suggest that polysilane decompositions (1) have similar intrinsic activation entropies (ΔS? ≈? 6.2 ± 5 e.u.) and (2) have activation energies which increase with increasing reaction endothermicities. Relative trapping efficiencies of SiH₄, Si₂H₆, Si₃H₈, C₄H₆, Me₃SiH, and H₂ toward SiH₂ and SiH₃SiH are also determined. Other results include the heat of formation of silylsilylene, ΔH ${}_{\text{°}}^{\text{f}}$ (SiH₃SiH) = 75.3 Kcal/mol, and the activation energy for 1,1-H₂ elimination from disilane (EH₂ = 57.8 kcal/mol).     

Sensitized photooxygenation of β-methoxystyrene and 1-(β-methoxyvinyl)naphthalene

Single oxygen can easily add to 1-(β-methoxyvinyl) naphthalene ($\text{1}$) with retention of sterochemistry to afford a stable 1,4-endoperoxide $\text{3}$. Sensitized photooxygenation of β-methoxystyrene ($\text{2}$) gives mainly Diels-Alder adducts of $\text{o}$-formylmethide quinone ($\text{12}$) which might be derived from initially formed 1,4-endoperoxide $\text{10}$.     

Stereoselective diels-alder reactions between 9-alkyl-1,4-dihydronaphthalen-1,4-imines and 2-alkylisoindoles

The Diels-Alder reaction between 9-alkyl-1,4-dihydronaphthalen-1,4-imines ($\text{1}$) and 2-alkylisoindoles ($\text{2}$) occurs in refluxing xylene to give exclusively the exo-endo cyclo-adducts $\text{3}$ ($\text{D}$).     

Relative asymmetric induction in the hydroboration of bi-1-cyclohexen-1-yls

Hydroboration-oxidation of the bi-1-cyclohexen-1-yls 1 and 8b gave single 1,4-diols, $\text{d,1}$ 2 and $\text{meso}$ 10b, respectively, whereas the chiral bi-1-cyclohexen-1-yl 8a, synthesized from (?)-$\text{trans}$-3,5-dimethylcyclohexanone, led to a mixture of two 1,4-diols (9a and 10a).