Copper-Catalyzed Allylation of Carbonyl Derivatives Using Allyl(2-pyridyl)silanes

Abstract

[reaction: see text] We have developed an efficient copper-catalyzed allylation of carbonyl derivatives using allyl(2-pyridyl)silanes, in which the strong directing effect of the 2-pyridyl group was observed. A useful synthesis and allylation of substituted allyl(2-pyridyl)silanes is also described.

Coordination environment friendly silicon in copper(I) chloride π-complexes with tetravinylsilane and dimethyltetravinyldisiloxane

“…A similar ring deformation of copper halide tetramers has been found for example in the g 2 -olefin complex [Cu 4 Cl 4 (C 17 H 18 N 2 O 3 S) 2 ] (III) [40] but it concerns mainly the stretching of the tetrameric units (bond length of cross-linkage CuÁ Á ÁCl 4.100(4) Å) and does not cause their twisting. This peculiar stereochemical behavior may be related to a sandwich-type structure imposed by the large planar organic ligand, whereas in the case of I and II the silicon ligands do not show a high degree of steric rigidity.…”

“…So, first of all the Cu 4 Cl 4 chair-like units in both complexes show the twisting conformation which is most appropriate for II (see grey cells in Table 4) and is caused essentially by electronic effects due to the planarity of the Cu(I) coordination sphere and possible by C-HÁ Á ÁCl hydrogen bonds (for I C21Á Á ÁCl3 3.483(3) Å, C21-HÁ Á ÁCl3 141.8). A similar ring deformation of copper halide tetramers has been found for example in the g 2 -olefin complex [Cu 4 Cl 4 (C 17 H 18 N 2 O 3 S) 2 ] (III) [40] but it concerns mainly the stretching of the tetrameric units (bond length of cross-linkage CuÁ Á ÁCl 4.100(4) Å) and does not cause their twisting.…”

“…The structure of I consists of two crystallographically independent centrosymmetric Cu 4 Cl 4 units linked in turn by tetradentate TVS into the infinite chain ( Fig. 1).…”

“…It is reasonable to investigate such coordination systems since they serve as reactive precursors for the preparation of naked metal nanoparticles or their deposition onto surfaces or participate in the catalytic reaction path either as catalyst precursors or as intermediates [1][2][3][4][5][6]. To the best of our knowledge, the thermal decomposition of copper(I) polyvinylsiloxanes complexes sometimes occurs with the formation of size-controlled metal nanoparticles [7].…”

“…Some of such unsaturated molecules (tetraallylsilane and divinyltetramethyldisiloxane) have been already used for the construction of different copper(I) chloride complexes in our previous works [13,14]. As a continuation of the studies on the crystal engineering in CuCl-polysiloxanes systems we have employed tetravinylsilane (TVS) and 1,2-dimethyl-1,1,2,2-tetravinyldisiloxane (DMTVDS) to produce new complexes [Cu 4 Cl 4 (TVS)] (I) and [Cu 4 Cl 4 (DMTVDS)] (II). The obtained data can shed some light on the factors promoting construction of metal center coordination sphere arrangement, degree of its coordination unsaturation and appearance of Cu n Cl n -cluster, whose recognition leads to understand the ligand exchange process in catalytic and stoichiometric reactions with Cu(I) complexes stabilized by organopolysiloxanes.…”