Si–H activation by means of metal ligand cooperation in a methandiide derived carbene complex

Abstract

Si-H bond activation of a number of silanes via metal ligand cooperation in a carbene complex is reported. Thereby, the electronic flexibility of the carbene ligand allows for the activation via a unique mechanism with oxidative addition to an 18e species without a formal change in the number of valence electrons.

Versatile Modes of Cooperative B−H Bond Activation Reactions in Ruthenium‐Carbene Complexes: Addition, Ring‐Opening and Insertion

“…Independent of the polarity of the E−H bond, these reactions resulted in the 1,2‐addition of the corresponding bond across the M δ+ =C δ− double bond with protonation of the carbenic carbon atom. Contrary to complexes with PCP pincer ligands, this was also the case for the hydridic Si−H bond in silanes . We reasoned that with the more electrophilic boranes different selectivities might be observed, also depending on the nature of the borane.…”

Preparation and Isolation of a Chiral Methandiide and Its Application as Cooperative Ligand in Bond Activation

“…Most of the metal complexes employed make use of chiralp hosphine ligands as source of stereoinformation. [12,13] Because of this applicationo fm ethandiidesa s cooperating ligands, the preparation of chiral derivatives and metalc omplexes thereof would be desirable. Because of their strong donor ability,c arbenes were found to be excellent ligands to support robustm etal complexes active in av ariety of different reactions, [3] including asymmetric transformations.…”

“…[4] Typically,c arbene ligands act as so-called spectator ligands, solely controlling transformationsa tthe metal center by manipulating its electronic ands tericp roperties. [12,13] Because of this applicationo fm ethandiidesa s cooperating ligands, the preparation of chiral derivatives and metalc omplexes thereof would be desirable. [5] Particularly,n ucleophilic carbene complexes with late transition metals have provent ob ea pplicable in this chemistry.…”

“…[5] Particularly,n ucleophilic carbene complexes with late transition metals have provent ob ea pplicable in this chemistry. [12,13] Because of this applicationo fm ethandiidesa s cooperating ligands, the preparation of chiral derivatives and metalc omplexes thereof would be desirable. [7] These ligands allowed the isolation of as eries of unique complexes with metal-carbon bondsv aryingb etween predominantly electrostatic interactions and "real" metal-carbon doubleb onds.…”

“…Isolation gave the SÀH (3), S1ÀP1 2.0030(11), S3ÀP2 2.010(1), S1'ÀP1' 2.0040(10),S 3'ÀP2' 2.0070(10), S2ÀO1 1.492(2), S2ÀN1 1.589(2), S4ÀO2 1.495(2),S 4 ÀN2 1.586(2), S2'ÀO1' 1.494(2), S2'ÀN1' 1.583(2), S4'ÀO2' 1.500(2), S4'ÀN2' 1.580(2), C1ÀLi32.180(6), C1ÀLi1 2.315(6), C21ÀLi6 2.179(6), C21ÀLi5 2.311(5), C1'ÀLi3' 2.190(5), C1'ÀLi1' 2.295(5), C21'ÀLi6' 2.202(6), C21'ÀLi5' 2.289 (5) (17), S2ÀO 1.445(4), S1ÀP1 .977(2), S2ÀN1 .583 (5), PÀC1 1.757 (7), PÀC2 1.801 (7);S 2-C1-P 123.5(4), S2-C1-Ru9 5.5(3), P-C1-Ru1 37.9(3); 5:R u ÀN2 .144(2), RuÀC1 2.160(3), RuÀS3, S1ÀP1 .9520(10),S2 ÀN1.553(2), 2.4291(8),S 2 ÀC1 1.756(2), PÀC1 1.812 (3);S2-C1-P1 14.38 (13). Treatment of as olution of (R S )-4 in toluene at À78 8Cw ith tert-butylthiol resulted in an immediate color change from blue to red and the selectivef ormation of as ingle new product (d P = 42.4 ppm).…”