Regiospecific Methylalumination of Silacyclopropenes: The Access to Z-1-Silyl-2-Aluminyl-Disubstituted Olefins.

A methodology to access Z-1-silyl-2-aluminyl-disubstituted olefins is developed. It relies on the uncatalyzed ring opening of silacyclopropenes in the presence of a stoichiometric amount of trimethylaluminum. The resulting heterosubstituted alkenes exhibit a particular interaction between the electron-rich [Si-CH] moiety and the electron-deficient diorganoaluminyl group, resulting in similar geometrical features due to the proximity of these two centers.

Photoresponsive Dioxazaborocanes-Containing Oligomers.

The synthetic methodology for the preparation of photoresponsive dioxazaborocanes-containing oligomers is developed. It relies on the transformation of the (diisopropylamino)boryl group (-BH(NiPr)) into a dioxazaborocane unit in the presence of β-aminodiols and involves a bis-borylated dithienylethene photochromic unit. The photophysical properties of the obtained oligomers are evaluated as well as their processability for the preparation of spin-coated films.

Synthesis of Photochromic Phosphines by Pd-Catalyzed Annulation Reaction of Alkynes Bearing Phosphinyl Substituent with a Silacyclopropene.

The synthesis of phosphines with light controlled basicity is presented in this study. A methodological approach for the preparation of these unconventional photochromic phosphines based on a dithienylethene organic moiety is reported. It relies on the palladium-catalyzed annulation of alkynyl phosphines in the presence of a 2,3-Dithienylsilacyclopropene.

1,2-Palladasilacyclobutene: The Missing Link in the Pd-Catalyzed Annulation of Alkynes for the Silirene-to-Silole Transformation.

The palladium-catalyzed annulation reaction of alkynes enables an attractive approach to siloles. Their access from silirenes and terminal alkynes proved rather general, involving reactive intermediates that have remained elusive to date. Starting from 1,2-bis(3-thienyl)silirene as a source of photochromic siloles, the mechanism of the annulation reaction has been revisited, and palladasilacyclobutenes resulting from the activation of the silirene could be isolated and thoroughly characterized (NMR, X-ray, and DFT).

Hydroboration of vinyl halides with mesitylborane: a direct access to (mesityl)(alkyl)haloboranes.

The direct access to (mesityl)(alkyl)haloboranes (Mes(Alk)BX) (X = Br, Cl) from mesitylborane dimer and vinyl halides is presented. The involved hydroboration reaction results in the transfer of the halogen atom from the carbon of the starting material to the boron in the final product. The reactivity of the obtained Mes(Alk)BX has been evaluated for the synthesis of the bipyridyl boronium cations and 2-arylpyridine derived boron N^C-chelates.