- Geometric E→Z Isomerisation of Alkenyl Silanes by Selective Energy Transfer Catalysis: Stereodivergent Synthesis of Triarylethylenes via a Formal anti-Metallometallation
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An efficient geometrical E→Z isomerisation of alkenyl silanes is disclosed via selective energy transfer using an inexpensive organic sensitiser. Characterised by operational simplicity, short reaction times (2 h), and broad substrate tolerance, the reaction displays high selectivity for trisubstituted systems (Z/E up to 95:5). In contrast to thermal activation, directionality results from deconjugation of the π-system in the Z-isomer due to A1,3-strain thereby inhibiting re-activation. The structural importance of the β-substituent logically prompted an investigation of mixed bis-nucleophiles (Si, Sn, B). These versatile linchpins also undergo facile isomerisation, thereby enabling a formal anti-metallometallation. Mechanistic interrogation, supported by a theoretical investigation, is disclosed together with application of the products to the stereospecific synthesis of biologically relevant target structures.
- Fa?bender, Svenja I.,Molloy, John J.,Mück-Lichtenfeld, Christian,Gilmour, Ryan
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p. 18619 - 18626
(2019/11/16)
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- Poly(silvinylene)s and a process for their preparation
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A process for preparing a poly(silvinylene) represented by the following general formula [III]: STR1 characterized in that (A) a polysilane represented by the following general formula [I]: STR2 and (B) an acetylene represented by the following general fo
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- Unified synthesis of vinylsilanes and silylated butadienes. Nickel-catalyzed olefination and silylolefination of dithioacetals
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A simple unified reaction has been developed in the syntheses of various vinylsilanes and silylated butadienes by the nickel-catalyzed coupling of dithioacetals with appropriate Grignard reagents. Reactions of 2-aryl-2-(trimethylsilyl)dithianes with MeMgI
- Ni, Zhi-Jie,Yang, Pin-Fan,Ng, Dennis K. P.,Tzeng, Yih-Ling,Luh, Tien-Yau
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p. 9356 - 9364
(2007/10/02)
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- Formation and Reactions of Olefins with Vicinal Silyl and Stannyl Substituents
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The silicon-tin bond in Me3SiSnR3 (R=Me, n-Bu) adds regio- and stereospecifically to 1-alkynes and also to a limited number of nonterminal alkynes when Pd(PPh3)4 is added as a catalyst.The use of the (Z)-silylstannylalkenes thus formed in synthesis either
- Mitchell, T. N.,Wickenkamp, R.,Amamria, A.,Dicke, R.,Schneider, U.
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p. 4868 - 4874
(2007/10/02)
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- SILAFUNCTIONAL COMPOUNDS IN ORGANIC SYNTHESIS. XVIII. OXIDATIVE CLEAVAGE OF THE SILICON-CARBON BOND IN ALKENYLFLUOROSILANES TO CARBONYL COMPOUNDS: SYNTHETIC AND MECHANISTIC ASPECTS
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Alkenyltrifluorosilanes are readily oxidized by one equivalent of MCPBA in DMF even at -50 deg C to give the corresponding carbonyl compounds via cleavage of the carbon-silicon bond.With three equivalent of MCPBA a concomitant cleavage of the carbon-carbon bond occurs.A plausible mechanism of these new types of oxidation has been discussed.Oxidation with DABCO*2H2O2 has also been described.
- Tamao, Kohei,Akita, Munetaka,Kumada, Makoto
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