The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform

Herbert Mayr - One of the best experts on this subject based on the ideXlab platform.

Mirjam Herrlich - One of the best experts on this subject based on the ideXlab platform.

Nathalie Hampel - One of the best experts on this subject based on the ideXlab platform.

Alejandro Perez-luna - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis of allenylzinc reagents by 1,2-rearrangement of alkynyl(disilyl)zincates derived from acetylenic epoxides and acetylenic aziridines
    Comptes Rendus Chimie, 2017
    Co-Authors: Valentin N. Bochatay, Laurent Debien, Fabrice Chemla, Franck Ferreira, Olivier Jackowski, Alejandro Perez-luna
    Abstract:

    Abstract Lithium alkynyl(disilyl)zincates obtained from metalated ethynyloxiranes, as well as from N - tert -butanesulfinyl(ethynyl)aziridines or N - tert -butanesulfonyl(ethynyl)aziridines, undergo 1,2-migration of the Organosilyl Group with ring opening of the oxirane or aziridine ring by S N i displacement. A developed protocol that involves n BuLi for the metalation step offers a straightforward approach to the corresponding δ-oxy- and δ-amino α-silyl allenylzinc intermediates. The reagents derived from the epoxides are amenable to subsequent in situ condensation with aldehydes or ketones to provide 1,3-diols but not those derived from aziridines that only react sluggishly in similar condensations.

Stefan Schmatz - One of the best experts on this subject based on the ideXlab platform.

  • Unimolecular Rearrangement Reactions in SilylpyrazolonesA Theoretical Approach
    Organometallics, 2002
    Co-Authors: Stefan Schmatz
    Abstract:

    Due to the easy migration of silyl Groups, the chemistry of silylpyrazolones exhibits various unimolecular reaction channels not encountered in conventional pyrazolone chemistry. The unimolecular rearrangement process starting from the CH form of N-(trimethylsilyl)-pyrazolone (which is primarily formed in the intramolecular condensation reaction of silylhydrazones) is investigated by density functional (B3LYP) and ab initio (MP2) calculations. The transition states are discussed in detail. First, the Organosilyl Group migrates from the nitrogen atom to the oxygen atom (1,3-Si shift). The second and third steps consist of two consecutive 1,2-H shifts from the carbon to the nitrogen atom. The barriers for the hydrogen migrations determine the overall classical barrier. In comparison to the reactant CH form, the most stable isomer O-silylpyrazolone is lower in energy by 5 kcal mol - 1 . This finding is in agreement with the experimental result. The calculated structure of this isomer is compared with X-ray diffraction data. The OH and NH forms of N-(trimethylsilyl)-pyrazolone are slightly higher in energy than the CH form.