2764-87-6Relevant academic research and scientific papers
Ruthenium-Catalyzed Site-Selective Intramolecular Silylation of Primary C-H Bonds for Synthesis of Sila-Heterocycles
Fang, Huaquan,Hou, Wenjun,Liu, Guixia,Huang, Zheng
, p. 11601 - 11609 (2017/08/30)
Incorporating the silicon element into bioactive organic molecules has received increasing attention in medicinal chemistry. Moreover, organosilanes are valuable synthetic intermediates for fine chemicals and materials. Transition metal-catalyzed C-H silylation has become an important strategy for C-Si bond formations. However, despite the great advances in aromatic C(sp2)-H bond silylations, catalytic methods for aliphatic C(sp3)-H bond silylations are relatively rare. Here we report a pincer ruthenium catalyst for intramolecular silylations of various primary C(sp3)-H bonds adjacent to heteroatoms (O, N, Si, Ge), including the first intramolecular silylations of C-H bonds α to O, N, and Ge. This method provides a general, synthetically efficient approach to novel classes of Si-containing five-membered [1,3]-sila-heterocycles, including oxasilolanes, azasilolanes, disila-heterocycles, and germasilolane. The trend in the reactivity of five classes of C(sp3)-H bonds toward the Ru-catalyzed silylation is elucidated. Mechanistic studies indicate that the rate-determining step is the C-H bond cleavage involving a ruthenium silyl complex as the key intermediate, while a η2-silene ruthenium hydride species is determined to be an off-cycle intermediate.
Rhodium-catalyzed intramolecular silylation of unactivated C(sp 3)-H bonds
Kuninobu, Yoichiro,Nakahara, Takahiro,Takeshima, Hirotaka,Takai, Kazuhiko
, p. 426 - 428 (2013/03/13)
The treatment of a variety of hydrosilanes, each incorporating a benzylic C(sp3)-H bond, with a rhodium catalyst resulted in intramolecular dehydrogenative silylation. This silylation reaction was found to occur at typically unreactive C(sp3)-H bonds located at terminal positions on alkyl chains. Interestingly, the rhodium catalyst also promoted regioselective silylation at a site internal to an alkyl chain.
Chemistry of o-Xylenediyl-Metal Complexes. Part 5. Silicon and Tin Metallacycles derived from o-C6H4(CHR)2 (R = H or SiMe3)
Lappert, Michael F.,Leung, Wing-Por,Raston, Colin L.,Skelton, Brian W.,White, Allan H.
, p. 775 - 786 (2007/10/02)
Treatment of SnCl2Ph2 with 6 or 2 7 in OEt2 yields the stannacycle 1 or 2 ((LL)2- = o-C6H4(CH2)2, (L'L')2- = o-C6H42, thf = tetrahydrofuran, tmen = Me2N2NMe2).Likewise, SnCl4 with 6 or 7 at 30 deg C in OEt2 affords exclusively the stannaspirobicycle 3 or 4; by contrast SnCl4 with 7 at -78 deg C gives, together with 4 (52percent), the yellow, diamagnetic tin(II) metallacycle 5 (14percent).Compound 5 is more conveniently prepared by treating Sn(OC6H2But2-2,6-Me-4)2 with 7; it is tetrameric in the solid and in solution, but monomeric in the gas phase and has a low first ionisation energy (7.6 eV).The compound 8 is obtained by an in situ Grignard reaction from SiCl2Me2, o-C6H4(CH2Cl)2 and Mg in thf, while 9 is prepared from SiCl2Me2 and 7.Each of the metallacycles derived from the ligand (L'L')2- was obtained stereospecifically as the meso diastereomer.X-Ray structure determinations of complexes 1-5 have been performed.The α,α'-unsubstituted metallacycles have shorter α> distances (2.144 in 1, 2.147 Angstroem in 3) than the corresponding α,α'-bis(trimethylsilyl) derivatives (2.166 in 2, 2.174 Angstroem in 4).The C6CαCα-o-xylenediyl plane is folded relative to the MCαCα plane, the fold angle Θ being 8.5 (1), 19.8 (2), 0.8 and 11.9 (3) 24.1 and 23.0 (4) and 20.8 deg (5).The larger Θ values for the complexes 2 and 4 than for their counterparts 1 and 3 (as for comparable SnC-α distances) is attributable to greater interligand strain and crowding around the metal centre in 2 and 4.Molecules of 5 have 4 symmetry, with Sn-Sn 2.852(3), Sn-Cα 2.15(3) and Sn-Cα' 2.09(4) Angstroem.
Rates and Mechanism for the Solvolyses of 2,2-Dimethyl-2-sila-1-indanyl Bromide and α-Trialkylsilylbenzyl p-Toluenesulfonates. α-Silicon Effect on the Stability of Benzylic Cations in Solution
Shimizu, Nobujiro,Osajima, Erika,Tsuno, Yuho
, p. 1145 - 1152 (2007/10/02)
α-Silicon effect on the benzylic solvolysis has been investigated.The solvolysis of 2,2-dimethyl-2-sila-1-indanyl bromide in aq acetone exhibits a linear response to the solvent ionizing power YBr, with a slope m close to unity (m = 0.93) and g
Arenes Disubstituted with Primary Alkyl Groups from Xylylene Dianions
Bates, Robert B.,Ogle, Craig A.
, p. 3949 - 3952 (2007/10/02)
Xylenes were converted into dianions 1.Reaction of dianions 1 with dialkyl sulfates gave symmetrical dialkylbenzenes 2 (R = R'), while methyl iodide caused oxidative coupling followed by alkylation to give 8.Unsymmetrical dialkylbenzenes 2 (R =/= R') were made by an indirect route involving monoanions 9 and 11.Reactions of dianions 1 with dihalides gave cyclophanes o-3 (n = 5,6,9), m-3 (n = 8-10), and p-3 (n = 9-11) and cyclophanes o-4 (n = 2,5,7,9) and m-4 (n = 2,6,7).Dianion 5 from 2,6-lutidine was used to prepare nitrogen analogues of 2 (R = R') and m-3 (n = 8-10).
