- Stereogradient polymers formed by controlled/living radical polymerization of bulky methacrylate monomers
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(Chemical Equation Presented) Life RAFT: A bulky methacrylate monomer, triphenylmethyl methacrylate (TrMA), was polymerized with reversible addition-fragmentation chain transfer (RAFT) agents. Stereogradient polymers in which the isospecificity increased
- Ishitake, Kenji,Satoh, Kotaro,Kamigaito, Masami,Okamoto, Yoshio
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- Nucleophilic acyl substitutions of anhydrides with protic nucleophiles catalyzed by amphoteric, oxomolybdenum species
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(Chemical Equation Presented) Among six different group VIb oxometallic species examined, dioxomolybdenum dichloride and oxomolybdenum tetrachloride were the most efficient catalysts to facilitate nucleophilic acyl substitution (NAS) of anhydrides with a myriad array of alcohols, amines, and thiols in high yields and high chemoselectivity. In contrast to the well-recognized redox chemical behaviors associated with oxomolybdenum(VI) species, the catalytic NAS was unprecedented and tolerates virtually all kinds of functional groups. By using benzoic anhydride as a mediator for in situ generation of an incipient mixed anhydride-MoO2Cl2 adduct with a given functional alkanoic acid, one can achieve oleate, dipeptide, diphenylmethyl, N-Fmoc-α-amino, pyruvic, and tert-butylthio ester, N-tert-butylamide, and trityl methacrylate syntheses with appropriate protic nucleophiles. The amphoteric character of the Mo=O unit in oxomolybdenum chlorides was found to be responsible for the catalytic NAS profile as supported by a control NAS reaction of using an authentic adduct-MoOCl2(O2-CBu t)2 between pivalic anhydride and MoO2Cl 2 as the catalyst.
- Chen, Chien-Tien,Kuo, Jen-Huang,Pawar, Vijay D.,Munot, Yogesh S.,Weng, Shieu-Shien,Ku, Cheng-Hsiu,Liu, Cheng-Yuan
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p. 1188 - 1197
(2007/10/03)
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- Process for preparing triarylmethyl methacrylate
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A triarylmethyl methacrylate is produced by reacting methacrylic acid with a triarylmethylating agent in an inert, organic solvent containing therein an excess amount of an amine or in the presence of an anion exchanger.
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- EASY PREPARATION OF TRIPHENYLMETHYL CARBOXYLATES.
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A new method for triphenylmethylation of carboxylic acids and phenol is disclosed.
- Hashimoto,Hayashi,Noyori
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p. 1431 - 1432
(2007/10/02)
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- A FACILE PROCEDURE FOR O-TRITYLATION
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The title operation is achieved via readily accessible organosilicon compounds.
- Murata, S.,Noyori, R.
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p. 2107 - 2108
(2007/10/02)
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- TRIMETHYLSILYL TRIFLATE IN ORGANIC SYNTHESIS
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Trimethylsilyl triflate is a powerful silylating agent for organic compounds and acts as a catalyst which accelerates a variety of nucleophilic reactions in aprotic media.The reactions proceed via one-center, electrophilic coordination of the silyl group to hetero functional groups and exhibit unique selectivities.
- Noyori, R.,Murata, S.,Suzuki, M.
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p. 3899 - 3910
(2007/10/02)
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