82772-29-0

Upstream product

• 100-52-7 benzaldehyde 
• 62-53-3 aniline 
• 18162-48-6 tert-butyldimethylsilyl chloride 
• 184368-89-6 1-iodo-2-(tert-butyldimethylsilyloxy)benzene 
• 115750-83-9 (2-bromophenoxy)(tert-butyl)dimethylsilane 

Downstream Products

• 140840-53-5 3-(tert-butyldimethylsilyl)-2-hydroxybenzaldehyde 
• 86998-00-7 o-(tert-butyldimethylsilyl)anisole 

Relevant academic research and scientific papers

Tuning the cytotoxicity of ruthenium(ii) para-cymene complexes by mono-substitution at a triphenylphosphine/phenoxydiphenylphosphine ligand

The new complexes [RuCl2(η6-p-cymene)(κP-Ph2PR)] [R = 4-C6H4OSiMe2tBu, 1; R = 4-C6H4Br, 2; R = OC(O)CHCl2, 3; R = OPh, 4; R = O(2-C6H4SiMe2tBu), 5] and [Ru(C2O4)(η6-p-cymene){κP-Ph2PO(2-C6H4(SiMe2tBu))}], 6, were obtained in 83-98% yield from Ru(ii) arene precursors by three different synthetic strategies. The unprecedented phosphine Ph2P(O(2-C6H4SiMe2tBu)) was synthesized in 86% yield from 2-C6H4Br(OSiMe2tBu) and Ph2PCl, via intramolecular oxygen to carbon 1,3 migration of the silyl group (retro-Brook rearrangement). All the complexes were fully characterized by analytical and spectroscopic methods, and by single crystal X-ray diffraction in the cases of 3, 4, 5 and 6. Complexes 1-6 and the model compounds [RuCl2(η6-p-cymene)(κP-PPh3)] (Ru-PPh3) and [Ru(C2O4)(η6-p-cymene)(κP-PPh3)] (Ru-PPh3-O) underwent slow degradation in chloroform solutions upon air contact; the mixed valence complex [(η6-p-cymene)Ru(μ-Cl)3RuCl2(κP-PPh3)], 7, was isolated from a solution of Ru-PPh3 in CHCl3, and X-ray identified. The antiproliferative activity of 1-6 and Ru-PPh3, Ru-PPh3-O and [RuCl2(η6-p-cymene)(κP-PTA)] (RAPTA-C) was assessed towards the triple-negative breast cancer cell line MDA-MB-231, the ovarian carcinoma cell line A2780 and human skin fibroblasts (HSF). Complexes 1, 2, 5 and 6 displayed IC50 values significantly lower than that of cisplatin, with 2 providing a more potent cytotoxic effect on MDA-MB-231 and A2780 cancer cells compared to the noncancerous cell line (HSF). The stability of all complexes in DMSO/water solution was elucidated by NMR and conductivity measurements, and in particular 35Cl NMR spectroscopy was helpful to check the possible chloride dissociation. The stability studies suggest that the cytotoxic activity in vitro of the compounds is mainly ascribable to Ru(ii) species still bound to the phosphorus ligand.

3-Hydroxy-2-(trialkylsilyl)phenyl Triflate: A Benzyne Precursor Triggered via 1,3-C-sp2-to-O Silyl Migration

3-Hydroxy-2-(trialkylsilyl)phenyl triflates are presented as new versatile hydroxyaryne precursors. These are base-activated aryne precursors induced via a C-sp2-to-O 1,3-Brook rearrangement. The reaction of various arynophiles and 3-trialkylsiloxybenzyne generated from 3-hydroxy-2-(trialkylsilyl)phenyl triflate efficiently afforded highly regioselective phenol derivatives. Furthermore, through crossover experiments, the intramolecular mechanism of silyl migration was demonstrated.

A practical ortho-rearrangement of silyl group of ortho-bromophenyl silyl ethers using magnesium(0)

A practical synthesis of ortho-silyl-substituted phenol from ortho-bromophenyl silyl ethers without using RLi is described. Various ortho-bromophenyl silyl ethers are treated with commercially available Mg turnings, which are easy to handle in air, and tr

Rhodium-catalyzed carbon-silicon bond activation for synthesis of benzosilole derivatives

A rhodium-catalyzed coupling reaction of 2-trimethylsilylphenylboronic acid with internal alkynes is developed for the synthesis of 2,3-disubstituted benzosilole derivatives. A range of functional groups, encompassing ketones, esters, amines, aryl bromides, and heteroarenes, are compatible, which provides rapid access to diverse benzosiloles. Sequential 2-fold coupling enables modular synthesis of asymmetrically substituted 1,5-dihydro-1,5-disila-s-indacene, a π-extended molecule of interest in organic electronics. In terms of the mechanism, the reaction involves cleavage of a C(alkyl)-Si bond in a trialkylsilyl group, which normally requires extremely harsh conditions for activation. Mechanistic studies, including effects of substituents, reveal that C-Si bond cleavage does not proceed through a hypercoordinated silicon species, but rather through a rhodium-mediated activation process. The potential use of the reaction in catalytic asymmetric synthesis of Si-chiral benzosiloles is also demonstrated.

Stereoselective ring-opening polymerization of a racemic lactide by using achiral salen- and homosalen-aluminum complexes

Highly isotactic polylactide or poly(lactic acid) is synthesized in a ring-opening polymerization (ROP) of racemic lactide with achiral salen- and homosalen-aluminum complexes (salenH2 = N,N′-bis(salicylidene) ethylene-1,2-diamine; homosalenH2 = N,N′-bis(salicylidene) trimethylene-1,3-diamine). A systematic exploration of ligands demonstrates the importance of the steric influence of the Schiff base moiety on the degree of isotacticity and the backbone for high activity. The complexes prepared in situ are pure enough to apply to the polymerizations without purification. The crystal structures of the key complexes are elucidated by X-ray diffraction, which confirms that they are chiral. However. analysis of the 1H and 13C NMR spec tra unambiguously demonstrates that their conformations are so flexible that the chiral environment of the complexes cannot be maintained in solution at 25°C and that the complexes are achiral under the polymerization conditions. The flexibility of the back-bone in the propagation steps is also documented. Hence, the isotacticity of the polymer occurs due to a chain-end control mechanism. The highest reactivity in the present system is obtained with the homosalen ligand with 2.2-dimethyl substituents in the backbone (ArCH=NCH2CMe2CH2N=CHAr), whereas tBuMe2Si substituents at the 3-positions of the salicylidene moieties lead to the highest selectivity (Pmeso,= 0.98; T m = 210°C). The ratio of the rate constants in the ROPs of racemic lactide and L-lactide is found to correlate with the stereoselectivity in the present system. The complex can be utilized in bulk polymerization, which is the most attractive in industry, although with some loss of stereoselectivity at high temperature, and the afforded polymer shows a higher melting temperature (Pmeso = 0.92, Tm up to 189°C) than that of homochiral poly(L-lactide) (Tm = 162-180°C). The "livingness" of the bulk polymerization at 130°C is maintained even at a high conversion (97-98%) and for an extended polymerization time (1-2 h).

Meta Functionalization of Anilines and Phenol

Base-promoted proton abstraction from ?-(N-tert-butyldimethylsilyl-N-methylaniline)chromium tricarbonyl (3) took place predominantly at the meta position and variously meta-substituted N-methylacetanilides 4 were obtained after reactions with electrophiles followed by oxidative decomplexation and N-acetylation.Application of the present method to variously N,N-disubstituted anilines 5 and phenols 7 was then examined and the corresponding meta substituted anilines 6 and phenol 9 were obtained.Keywords - metalation of aromatic ring; chromium tricarbonyl complex; tert-butyl dimethylsilyl protecting group; meta-substituted anilines; meta-substituted phenol; electrophilic substitution

META FUNCTIONALIZATION OF ANILINES AND PHENOL

Regioselective introduction of various functional groups on the meta-position of anilines and phenol was achieved by proton abstraction from chromium tricarbonyl complexes 3,5,7 with n-BuLi, followed by the addition of electrophiles and decomplexation.