We report the development of a new methodology for the preparation of cyclic tetrasubstituted alkenes with π-conjugated substituents. The synthesis of the target compounds was accomplished through the regioselective cross-coupling reaction of diphenyl bromocyclohexenyl phosphate with organo-zinc reagents. The procedure succeeded in the preparation of alkenes with two pyrene moieties. The absorption and photoluminescence spectra of the prepared compounds were measured.

Indole derivatives are associated with a variety of both biological activities and applications in the field of material chemistry. A number of different strategies for synthesizing substituted indoles by means of the reactions of indolylboronic acids with electrophilic compounds are considered the methods of choice for modifying indoles because indolylboronic acids are easily available, stable, non-toxic and new reactions using indolylboronic acids have been described in the literature. Thus, the aim of this review is to summarize the methods available for the preparation of indolylboronic acids as well as their chemical transformations. The review covers the period 2010–2019.

The present study investigated the ability of bromovinyl phosphates to react with organozinc reagents at room temperature during palladium-catalyzed reactions. It was determined that both the bromine atom and the phosphate group were successfully substituted by means of the reaction with the organozinc reagents, thereby allowing for the synthesis of cyclic and acyclic tetrasubstituted double bonds. The low stability of the organozinc compounds in an acidic environment was exploited to accomplish the synthesis of alkenes using a one-pot, two-step experimental setup.

A set of novel aromatic and heteroaromatic bench‐stable sulfoxide‐based boronates was prepared. The structure of the boronates was established by means of X‐ray crystallography, and the prepared boronates were successively used in Suzuki cross‐coupling reactions under different conditions. We also developed a tandem Suzuki reaction so that a base is generated during the nucleophilic addition of Grignard reagents to 4‐bromobenzaldehyde. The formed intermediates were smoothly coupled with the prepared boronates and the boronic acids under external base‐free conditions.magnified image

Palladium-catalyzed Suzuki reactions of brominated flavin derivatives (5-deazaflavins, alloxazines, and isoalloxazines) with boronic acids or boronic acid esters that occur readily under mild conditions were shown to be an effective tool for the synthesis of a broad range of 7/8-arylflavins. In general, the introduction of an aryl/heteroaryl group by means of a direct C−C bond has been shown to be a promising approach to tuning the photophysical properties of flavin derivatives. The aryl substituents caused a bathochromic shift in the absorption spectra of up to 52 nm and prolonged the fluorescence lifetime by up to 1 order of magnitude. Moreover, arylation of flavin derivatives decreased their ability to generate singlet oxygen.

This short review summarizes the latest advances in the cross-coupling reactions of double and triple electrophilic templates bearing halogen atoms and an activated C–O bond. Reactions involving the formation of a C–C bond as part of di-, tri-, and tetrasubstituted double bond systems are highlighted.1 Introduction2 Cross-Coupling Reactions of Halovinyl Tosylates3 Cross-Coupling Reactions of Halovinyl Triflates4 Cross-Coupling Reactions of Halovinyl Phosphates5 Cross-Coupling Reactions of Halovinyl Esters6 Conclusion

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The diastereoselective synthesis of tetrasubstituted cyclopropanes is described. The two-step procedure is based on the 3-exo-tet Michael addition-initiated ring closure. In the first step, the enolates derived from α,α-dibromoketones react with the α, -unsaturated Fischer alkoxycarbene complexes to [a] 431 Scheme 3. Conversion of cyclopropane 4 to ester 5.[a] The MIRC and demetallation was performed in a one-pot setup.[b] The cyclopropane 5aa was prepared from the tungsten carbene complex 4m.