η:η-Alkynyl-Bridged W−Si Complexes: Formation, Structure, and Reaction with Acetone
摘要:
Reactions of (eta5-C5Me4R)(CO)2(MeCN)WMe (R = Me, Et) with HPh2SiCCtBu gave the novel alkynyl-bridged W-Si complexes, (eta5-C5Me4R)(CO)2W(mu-eta1:eta2-CCtBu)(SiPh2) (R = Me, Et), whose alkynyl ligands bridge the tungsten and silicon atoms in an eta1:eta2-coordination mode. The structures of these complexes were fully characterized, including X-ray crystallography. Treatment of (eta5-C5Me5)(CO)2W(mu-eta1:eta2-CCtBu)(SiPh2) with acetone resulted in acetone insertion into the silicon-alkynyl linkage followed by intramolecular C-H activation of the tBu group to give the chelate-type alkyl-alkene complex, (eta5-C5Me5)(CO)2W(eta1:eta2-CH2CMe2C=CHSiPh2OCMe2).
Sodium triethylborohydride as a catalyst for the dehydrogenative silylation of terminal alkynes with hydrosilanes
作者:Maciej Skrodzki、Samanta Witomska、Piotr Pawluć
DOI:10.1039/c8dt00684a
日期:——
sodium triethylborohydride-catalyzed C(sp)–H bond silylation is reported. The reaction of aromatic and aliphatic alkynes with aromatic hydrosilanes and hydrosiloxanes proceeded in a highly selective manner to afford dehydrocoupling products. Competitive hydrosilylation of the terminalalkyne did not occur as a side-reaction. In view of the above it is remarkable that NaHBEt3 is commonly used as a reducing
Novel eta(3)-silapropargyl/alkynylsilyl complexes Cp*(CO)(2)Mo(eta(3)-Ph(2)SiCCR) (3a, R = (t)Bu; 3b, R = (i)Pr) were synthesized by the reactions of Cp*(CO)(2)(MeCN)MoMe (1) with alkynylsilanes HPh(2)SiC[triple bond]CR. The structures of 3a and 3b were fully characterized by NMR spectroscopy and X-ray crystallography. The reaction of 3a with MeOH at room temperature gave the stable four-membered metallacycle
Reactions of (eta5-C5Me4R)(CO)2(MeCN)WMe (R = Me, Et) with HPh2SiCCtBu gave the novel alkynyl-bridged W-Si complexes, (eta5-C5Me4R)(CO)2W(mu-eta1:eta2-CCtBu)(SiPh2) (R = Me, Et), whose alkynyl ligands bridge the tungsten and silicon atoms in an eta1:eta2-coordination mode. The structures of these complexes were fully characterized, including X-ray crystallography. Treatment of (eta5-C5Me5)(CO)2W(mu-eta1:eta2-CCtBu)(SiPh2) with acetone resulted in acetone insertion into the silicon-alkynyl linkage followed by intramolecular C-H activation of the tBu group to give the chelate-type alkyl-alkene complex, (eta5-C5Me5)(CO)2W(eta1:eta2-CH2CMe2C=CHSiPh2OCMe2).
Hydrosilylation and Hydrogermylation of CO
<sub>2</sub>
and CS
<sub>2</sub>
by Al and Ga Functionalized Silanes and Germanes – Cooperative Reactivity with Formation of Silyl Formates and Disilylacetals
alkynylelement hydrides iPr2E(H)–C≡C‐tBu (1; E = Si, Ge) with R2M–H [M = Al, Ga; R = tBu, CH(SiMe3)2] afforded in moderate yields the Al and Ga functionalized alkenylsilanes and ‐germanes iPr2E(H)C(MR2)=CH‐tBu (2). The air and moisture sensitive Alcompounds reacted with CO2 under mild conditions (room temperature, 1 bar) to yield the formates [iPr2EC(AlR2)=C(H)–tBu]O2CH (3) by C=O insertion into the E–H bond and
所述alkynylelement氢化物的Hydrometallation我镨2 E(2H)-C≡C-吨卜(1 ; E =硅,锗),其中R 2 M-H [M =铝,镓; R =吨卜,CH(森达3)2 ]在中等产率的Al和Ga官能alkenylsilanes和得到-germanes我镨2 E(H)C(MR 2)= CH-吨BU(2)。空气和湿气敏感的Al化合物在温和的条件下(室温,1 bar)与CO 2反应生成甲酸酯[ i Pr 2 EC(AlR 2)= C(H)– t通过C = O插入E–H键和第二个O原子与铝的配位来生成Bu] O 2 CH(3)。乙缩醛MeAl [C(Si i Pr 2)= CH- t Bu] 2 O 2 CH 2(4a)作为独特的副产物获得。路易斯酸较少的酸性Ga化合物2c即使在较高的温度和压力下也不会与CO 2反应。与CS 2反应生成二硫缩醛[ i Pr 2 EC(M
Reactions of Tungsten Acetylide–Silylene Complexes with Pyridines: Direct Observation of Silylene/Silyl Migration in Tungsten Acetylide and Carbyne/Vinylidene Frameworks
Reaction of acetylide-silylene complex Cp*-(CO)(2)W(SiPh2)((CCBu)-Bu-t) (1a) with 4-(dimethylamino)-pyridine (DMAP) gave an equilibrium mixture of DMAP-stabilized silylene acetylide complexes trans- and cis-Cp*-(CO)(2)W(SiPh2 center dot DMAP)((CCBu)-Bu-t) (trans-4 and cis-4). The corresponding reaction using Cp*(CO)(2)W(SiPh2)(CCSiMe3) (2) produced the novel DMAP-coordinated silenylcarbyne/silylvinylidene complex Cp*(CO)(2)W[CC(SiPh2 center dot DMAP)(SiMe3)] (6a) as a major product, which was equilibrated with trans- and cis-Cp*(CO)(2)W(SiPh2 center dot DMAP)(CCSiMe3) (trans-5a and cis-5a) via silylene/silyl migration. The novel structures of cis-4 and 6a were revealed by X-ray crystallography. A mixture of 2 and pyridine exhibited interesting temperature-dependent NMR spectral changes, indicating the formation of trans- and cis-Cp*(CO)(2)W(SiPh2 center dot py)(CCSiMe3) (trans-5b and cis-5b) and Cp*(CO)(2)W[CC(SiPh2 center dot py)(SiMe3)] (6b) at low temperature, while a mixture of la and pyridine showed no such spectral changes.