82772-30-3Relevant academic research and scientific papers
A practical ortho-rearrangement of silyl group of ortho-bromophenyl silyl ethers using magnesium(0)
Hasegawa, Takashi,Kishida, Hisanori,Nomura, Nobuyoshi
supporting information, p. 455 - 457 (2017/01/10)
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
Modular approach to silicon-bridged biaryls: Palladium-catalyzed intramolecular coupling of 2-(arylsilyl)aryl triflates
Shimizu, Masaki,Mochida, Kenji,Hiyama, Tamejiro
supporting information; experimental part, p. 9760 - 9764 (2009/05/30)
(Chemical Equation Presented) Bridge of Si: Intramolecular direct arylation of 2-(arylsilyl)aryl triflates is catalyzed smoothly by Pd(OAc) 2/PCy3 in the presence of Et2NH in dimethylacetamide (DMA), giving rise to the corresponding silicon-bridged biaryls in good to excellent yields. The new approach has led to the synthesis of a silicon-bridged 2-phenylindole (see scheme) that exhibits blue photoluminescence in the solid state with extremely high quantum yields.
Stereoselective ring-opening polymerization of a racemic lactide by using achiral salen- and homosalen-aluminum complexes
Nomura, Nobuyoshi,Ishii, Ryohei,Yamamoto, Yoshihiko,Kondo, Tadao
, p. 4433 - 4451 (2008/02/09)
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
Fukui, Mineo,Ikeda, Toshiya,Oishi, Takeshi
, p. 466 - 475 (2007/10/02)
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
Fukui, Mineo,Ikeda, Toshiya,Oishi, Takeshi
, p. 1605 - 1608 (2007/10/02)
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.
