(Z)‐1,2‐bis(ethoxydimethylsilyl)arylethenes as new building blocks for organic synthesis

Abstract

A new efficient synthetic protocol for highly stereoselective synthesis of (Z)-1,2-bis(ethoxydimethylsilyl)arylethenes from vinylsilanes based on sequential ruthenium-catalyzed silylative coupling-palladium-catalyzed Heck coupling is reported. Reactivity of title compounds towards carbon electrophiles in the catalytic desilylative arylation is discussed.

Pd Nanoparticle-Catalyzed Stereospecific Mizoroki–Heck Arylation of cis-1,2-Disilylarylethylenes

“…(E)-1,2-Bis(dimethylphenylsilyl)ethane yielded a mixture of Heck-and Hiyama-type coupling products, while the more electron-rich (E)-1,2-bis-(ethoxydimethylsilyl)ethane was a Heck-type selective product, leading to (Z)-1,2-bis(silyl)arylalkenes. 13 In our hands, this catalytic system consisting of Pd(OAc) 2 (3 mol %), PPh 3 (6 mol %), and AgNO 3 (1 equiv) in CH 3 CN was completely inefficient in performing any arylation in 1a. Contrary to Marciniec's work, 13 the Pd(OAc) 2 -catalyzed arylation of unactivated (E)-l,2-bis(trimethylsilyl)ethylene provided (Z)trimethyl(2-arylethenyl)silanes 14 via a highly stereoselective Hiyama coupling.…”

“…(d) Even ortho-substituted aryl iodides couple efficiently. In the 13 C NMR spectra of ortho-substituted arylation products (e.g., 2cd, 2dd, and 2fb), the pairs of formally equivalent carbon atoms on the non-ortho-substituted aromatic ring appear as non-equivalent, apparently due to the restricted rotation of the ortho-substituted aryl ring. (e) The arylation tolerates the presence in the aryl iodide of a ketone carbonyl group (2bb) or a phenol hydroxyl (2ad).…”

“…26 (Z)-(1-Phenylethene-1,2-diyl)bis(trimethylsilane) (1a). 20 Colorless liquid; 1 H NMR (500 MHz, CDCl 3 ) δ 7.27 (t, J = 7.5 Hz, 2H), 7.18 (t, J = 7.5 Hz, 1H), 7.04 (d, J = 7.5 Hz, 2H), 6.45 (s, 1H), 0.23 (s, 9H), 0.18 (s, 9H); 13…”

1-(Triethoxysilyl)buta-1,3-dienes—New Building Blocks for Stereoselective Synthesis of Unsymmetrical (E,E)-1,4-Disubstituted 1,3-dienes

“…In view of the above advantages, we have successfully applied various unsaturated organosilicon precursors such as ( E )-silylstyrenes [26,27,28], 1,1-bis(silyl)alkenes [29,30], ( E )-1,2-bis(silyl)alkenes [31] and vinylcyclosiloxanes [32] as versatile double-bond equivalents in the construction of π-conjugated systems.…”

“…The palladium-catalyzed and fluoride-promoted cross-coupling of unsaturated organosilicon compounds with aryl or alkenyl halides (Hiyama coupling) has been recently employed as a mild and efficient alternative to the well-established Stille, Negishi, and Suzuki reactions, taking intoaccount the commercial availability, high stability, and low toxicity of silicon derivatives [ 23 , 24 , 25 ]. In view of the above advantages, we have successfully applied various unsaturated organosilicon precursors such as ( E )-silylstyrenes [ 26 , 27 , 28 ], 1,1-bis(silyl)alkenes [ 29 , 30 ], ( E )-1,2-bis(silyl)alkenes [ 31 ] and vinylcyclosiloxanes [ 32 ] as versatile double-bond equivalents in the construction of π-conjugated systems.…”