Palladium-Catalyzed Dimerization Disilylation of 1,3-Butadiene with Chlorosilanes

Abstract

[reaction: see text] 1,3-Butadiene reacted with chlorosilanes and Grignard reagents at 20 degrees C in the presence of a catalytic amount of Pd(acac)(2) to give disilylated dimers 2 regioselectively, which have two silyl groups (R(3)Si) at the 3- and 8-positions of a 1,6-octadiene skeleton. When phenyl- or allyl-substituted chlorosilanes were used, coupling product was obtained stereo- as well as regioselectively, giving rise to only (E)-olefins. It is proposed that Pd-ate complexes play important roles in both C-Si bond-forming processes.

Nickel‐Catalyzed Dimerization and Alkylarylation of 1,3‐Dienes with Alkyl Fluorides and Aryl Grignard Reagents

“…[4] This reaction provides au seful method for introducing two different carbon moieties into the 2,6octadiene framework, although the three-component coupling of these reagents in a1:1:1 ratio competes or even occurs preferentially in some cases. [4a,c] We previously reported on the dimerization and arylsilylation [5] or disilylation [6] of 1,3-butadiene with chlorosilanes as the electrophile in the presence of aN io rP dc atalyst, respectively (Scheme 1c). This reaction is promoted by Grignard reagents,which enable the formation of an anionic nickel complex B as the catalytically active species.However, the use of asimple alkyl electrophile,such as an alkyl halide, in this transformation has not yet been achieved, mainly because of the rapid direct cross-coupling between alkyl halides and organometallic reagents.…”

Nickel‐Catalyzed Dimerization and Alkylarylation of 1,3‐Dienes with Alkyl Fluorides and Aryl Grignard Reagents

“…We previously reported on the dimerization and arylsilylation or disilylation of 1,3‐butadiene with chlorosilanes as the electrophile in the presence of a Ni or Pd catalyst, respectively (Scheme c). This reaction is promoted by Grignard reagents, which enable the formation of an anionic nickel complex B as the catalytically active species.…”

“…Telomerization and related transformations (Scheme a and b) are useful for constructing functionalized C8 frameworks, but often suffer from side reactions, including 1) the direct functionalization of the 1,3‐diene without dimerization and 2) oligomerization of the 1,3‐dienes,, and from poor product selectivities with respect to 3) the regioselectivity of C−C bond formation with nucleophiles and/or electrophiles– and 4) the stereochemistry of the newly formed internal C−C double bonds ,. In contrast, the present reaction resulted in perfect selectivities and appears to proceed through a unique mechanism that involves an anionic complex B as the active catalytic species.…”

Insertion of Phenylacetylene into Pt(SnMe3)2(PMe2Ph)2

“…The addition of group 14 element bonds is among the central subjects of such reactions. Typical examples include bis-silylation, bis-stannylation, silyl-stannylation, and silyl-borylation 5 of alkynes and dienes catalyzed by platinum-group metal complexes. While the catalytic reactions are commonly assumed to proceed via insertion of a C−C multiple bond into a group 14 element−platinum bond, detailed information about this elementary process has been extremely limited. , We have examined the mechanisms of alkyne insertion into bis(silyl), silyl(boryl), silyl(stannyl), and germyl(stannyl) complexes of platinum .…”