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The photoextrusion of the SO-bridge of 7-thiabicyclo[2.2.1]hept-2-ene 7-oxides is discussed. An analysis of all the major by-products in the exemplary case of the photo reaction of 3a is given. The existence of intermediate dienes 4 has been established. Data on a comparative photoextrusion of an epithio-bridge of 7-thiabicyclo[2.2.1]-hept-2-ene (6) are provided.

Benzamides were converted into benzonitriles with BrCCl3–PPh3–Et3N in CH2Cl2 in an Appel-type reaction. Benzaldoximes could be transformed to benzonitriles under identical conditions. It was found ...

A new one-pot, two-step protocol for the combined Wittig-Heck reaction using aldehydes, e.g. (I) and (V), preformed ylides such as (III) and acrylates or styrenes leads predominantly to E-configurated products.

α-Benzocycloalkenones in general form benzocycloalkadienes when they are subjected to reactions with neopentyl glycol or other alkanediols under forced conditions.

4-Bromo- and 4-Chloro-3-t-butylphenol, two potent fungistatics, were prepared in an efficient 3-step synthesis from commercially available materials. Crucial to the synthesis is the use of halo-substituents as positional protective groups.

The synthesis of the thiopheno crown ethers 4 is described. The oxidative cycloaddition of these and the known thiopheno crown ethers 2 with N-phenylmaleimide is reported. The resulting sulfoxy-bridged cycloadducts 15 and 16 are transformed oxidatively into the phthalimido crown ethers 14 and 17. An X-ray crystal-structural analysis of the cycloadduct 16b is provided. The complexation behaviour of the crown ethers towards alkali-metal and silver cations is investigated.

Irradiation (λ > 390 nm) of 2H-1-benzothiopyran-2-one (1) in the solid state affords selectively 6aα,6bα,12bα,12cα -tetrahydrocyclobuta[1,2-c:4,3-c′]bis[1]benzothiopyran -6,7-dione (2), the head-to-head (HH) cis-cisoid-cis-dimer, while irradiation of 1 in the solid state using shorter wavelengths (λ > 340 nm) affords a mixture of all four cis-fused tricyclic dimers 2–5. These results represent a novel wavelength effect in solid-state photochemistry.

Steroids are an important source of chiral mesophases. The melting behavior and mesomorphic properties of homologous series of steroidal derivatives have been extracted from the literature, tabulated, and discussed. The tables provide the reader with an evaluated compilation of the type of mesophases found for the individual compounds, including their transition temperatures. Where the literature gives more than one set of data for a specific substance, one has been chosen as the main reference, but all alternatives are listed in the footnotes. The data can be used for statistical analysis to show the specific role of substructures within the steroidal framework.

Thiophenes 1 were treated with m-chloroperbenzoic acid (m-CPBA) under BF(3).Et(2)O catalysis to afford thiophene S-monoxides. These could be reacted in situ as intermediary species with a number of dienophiles to provide arenes (with alkynes as dienophiles) or 7-thiabicyclo[2.2.1]hept-2-ene 7-oxides (with alkenes as dienophiles). It was also possible to isolate thiophene S-monoxides in solution and to cycloadd them in a second step. In either way it could be shown that the use of BF(3).Et(2)O enhances the yields of the oxidative cycloaddition of thiophenes considerably. Moreover a greater variety of dienophiles (29a, 29b, 29c) could be reacted with thiophenes than in the case of the noncatalyzed reaction. All cycloadditions catalyzed by BF(3).Et(2)O give only a single diastereoisomer as cycloadduct. The reactions show a high pi-facial selectivity, a fact that can be explained by the Cieplak-effect. Without added dienophiles, 2-methylthiophene (1e) gave a single dimer (36) of 2-methylthiophene S-monoxide, whereas 2,5-dimethylthiophene (1a) gave three dimers (32a-c). In the case of tetrasubstituted thiophenes, thiophene S-monoxides (e.g., 31b and 31c) could be isolated in substance.

Photooxygenation of 4,5,6,8,16-pentamethyl[2.2]metacyclophane 6 gives [2.2]metacyclophane endoperoxide 7; its X-ray crystallographic analysis and stability in the thermal deoxygenation reaction are reported.

The oxidative cycloaddition of 3,4-dibromo-[n](2,5)thiophenophanes 12b–e and (2,4)[8]thiophenophane 16 with dienophiles gave stereoselectively OS-bridged cycloadducts 18, 19 and 24. The X-ray analysis of cycloadduct 18a shows it to have a rigid conformation. The molecules can be regarded as a new series of paddlanes. Under the same oxidative conditions, 3,4-dibromo-[8](2,5)thiophenophane (12a) gave the two dimers 29 and 30. The results of the X-ray analysis of 29 are discussed.

The reactivity of a number of chloroarenes was investigated and chloro―nitroarenes were found to undergo facile arylation with Pd(PPh 3 ) 4 / [Pd(PPh 3 ) 2 Cl 2 /nPPh 3 ] as catalyst. Furthermore, 4-chlorobenzaldehyde underwent arylation under the conditions, albeit with a higher catalyst loading.

Two novel, strained trans-10b,10c-dihydropyrenes, 9a–b, with internal, bulky trimethylsilylmethyl substituent(s) were synthesized. Their 14π-electron annulene systems were found to be distorted, as shown by X-ray crystallographic analyses and 1H-NMR and UV spectroscopy.

Rigid, layered hetareno/hetareno- and hetareno/areno-cyclophanes with closely held, non-distorted, interacting π-systems can be synthesized easily by using various building blocks.

Novel rearrangement of intermediate carbocations generated from rigid, layered [3.3]orthocyclophane-alcohols 4 are presented. The bicyclo[4.4.1]undecane framework of 4 rearranges to either bicyclo[5.4.0]- 5 and/or bicyclo[4.4.0]- 6 or tricyclo[5.4.0.02,11]- ring-system 11, depending upon the nature of the aryl substituent on the bridging tertiary carbon atom. X-Ray crystal structure analyses have been performed on the rearrangement products.

A number of 7-ω-carboxamidoalkyl-substituted estra-1,3,5(10),6-tetraenes as potential ligands for the estrogen receptor ERa have been prepared using either a conjugate addition of α,ω-iodoalkanenitriles or a Michael addition to steroidal ketone 3 as the key step.

Raney Ni-Al alloy in a dilute aqueous alkaline solution has been shown to be a very powerful reducing agent and is highly effective for the reductive dehalogenation of polyhalogenated phenols and a...

Raney Ni–Al alloy in a dilute aqueous alkaline solution has been shown to be a very powerful reducing agent in the hydrogenation of phenol and alkylated phenols to the corresponding cyclohexanol de...

Raney Ni‐Al alloy in a dilute alkaline aqueous solution has been shown to be a powerful reducing agent, which is highly effective in the reduction of benzophenones to the corresponding hydrocarbon derivatives, in the absence of any organic solvents.

Tetracyclones are transformed to a mixture of diacylstilbenes and α-pyrones, when they are heated in diphenylether saturated with oxygen.

A number of α-alkoxyestradiols were prepared through LiAlH4 reduction of a suitably protected 6α,7α-epoxyestra-1,3,5(10)-trien-3-ol-17-one, alkylation of the resultant 7α-hydroxyestra-1,3,5(10)-trien-3-ol-17-one derivative and subsequent transformation of the C17 functionality. The stereochemistry of the products was investigated by 2D NMR spectroscopy.

Benzo[b]thiophene S,S-dioxide can be transformed by cycloaddition with tetraarylthiophene S-oxides to tetraaryldibenzothiophene S,S-dioxides. An analogous cycloaddition of benzo[b]thiophene S,S-dio...

In the presence of platinum on carbon (Pt/C), (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-en-1-ols react with primary and secondary alcohols to give (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-enyl ethers.

Tris(triphenylphosphine)cuprous chloride [Cu(PPh3)3Cl] has been found to be an efficient catalyst for the dehydrosilylation of carboxylic acids with silanes. In the presence of 4 mol% Cu(PPh3)3Cl, dehydrosilylation reactions in acetonitrile afforded the corresponding silyl esters at 80°C in good yields. It was noted that triphenylphosphine itself also functions as an adequate catalyst for the reaction.

Triphenylphosphine has been found to be an efficient catalyst for the dehydrosilylation of carboxylic acids with silanes. In the presence of 4 mol% of triphenylphosphine (PPh 3 ), dehydrosilylation reactions in DMF afforded the corresponding silyl esters at 120 °C in good yield.