Dimerisation silylative

Ruhlmann and co-workers found194-196 that carboxylic acid esters react under dimerisation to form acyloins if they are treated with sodium/TMS-Cl (142) in inert solvents. This Bouveault-Blanc-like synthesis has many parallels to the reductive silyl-ation (vide supra). 

Although finding relatively wider synthetic use than the alkenylsilver compounds, examples of reactions of the perfluoroalkenylsilver compounds are limited to a handful of reactions, including protolysis, bromination, dimerisation, methylation, and silylation (Schemes 1.28 and 1.29).69,70... 

Thiopropenoylsilanes 42, readily accessible from silylated allenes, self-dimerise in a head-to-head fashion to give silylated 1,2-dithiins sometimes the corresponding 1,3-dithiin is also formed <03TL2831>. 

The 3,6-disilylated-3-vinyl-l,2-dithiins 38, obtained by the self-dimerisation of silylated allenes, undergo a Lewis aeid-promoted rearrangement to the bicyclic endodisulfide <05TL4711>. Tethered bilayer lipid membranes have been obtained using 4-hydroxy-l,2-dithianes as the anchor for coupling reactions with the lipid <05AJC738>. 

The cationic Ru complex 4 also promotes silylative dimerisation of aromatic aldehydes with hydrosilanes. For example, the reaction of benzaldehyde and triethylsilane in the presence of a catalytic amount of 4 affords the dimerisation product 19 along with a small amount of the hydrosilylation product PhCH20SiEt3 (Equation 7). This type of silylative dimerisation of aldehydes is relatively scarce in the literature common ruthenium complexes such as [RuCl2(PPh3)3] and [Ru3(CO)j2] give only the hydrosilylation products. 

CpCo(C0>2 catalyses the dimerisation of Me SiC=CSiMe to the butaaiene, and the C2+2+23 cycloaddition of silylated enediynes to give the A ring of... 

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