112383-49-0Relevant academic research and scientific papers
Dimethylaminopyridine-supported graft polymer catalyst and its flow system
Okuno, Yoshinori,Isomura, Shigeki,Kamakura, Takahiro,Sano, Fumiaki,Tamahori, Kaoru,Goto, Takahiro,Hayashida, Takahiro,Kitagawa, Yuuichi,Fukuhara, Ami,Takeda, Kazuyoshi
, p. 1711 - 1715 (2015)
A new heterogeneous organocatalyst, graft polymer supported dimethylaminopyridine (g-DMAP), is developed. This catalyst has a flexible structure and comprises DMAP anchored to the polyethylene-graft-polyacrylic acid (PE-g-PAA). It exhibits higher activity than DMAP supported on polystyrene cross-linked with divinylbenzene and can be recovered in batch mode acetylation. The activity and stability of this catalyst allow its application in continuous flow systems. Continuous acetylation proceeds with excellent conversion, and a turnover number of 560 can be achieved using g-DMAP. Parallel fixed bed reactors were used to scale up the synthesis of this continuous flow system. Eight parallel fixed bed reactors displayed excellent conversion.
Mutant lipase-catalyzed kinetic resolution of bulky phenyl alkyl sec-alcohols: A thermodynamic analysis of enantioselectivity
Vallin, Michaela,Syren, Per-Olof,Hult, Karl
, p. 411 - 416 (2010)
The size of the stereoselectivity pocket of Candida antarctica lipase B limits the range of alcohols that can be resolved with this enzyme. These steric constrains have been changed by increasing the size of the pocket by the mutation W104A. The mutated enzyme has good activity and enantioselectivity toward bulky secondary alcohols, such as 1-phenylalkanols, with alkyl chains up to eight carbon atoms. The S enantiomer was preferred in contrast to the wild-type enzyme, which has R selectivity. The magnitude of the enantioselectivity changes in an interesting way with the chain length of the alkyl moiety. It is governed by interplay between entropic and enthalpic contributions and substrates with long alkyl chains are resolved best with E values higher than 100. The enantioselectivity increases with temperature for the small substrates, but decreases for the long ones.
Expanding substrate scope of lipase-catalyzed transesterification by the utilization of liquid carbon dioxide
Hoang, Hai Nam,Matsuda, Tomoko
, p. 7229 - 7234 (2016/10/26)
Secondary alcohols having bulky substituents on both sides of the chiral center are often poor substrates for most lipases. Here we reported that substrate scopes of two of the most used lipases, Candida antarctica lipase B and Burkholderia cepacia lipase, were found to be expanded toward more bulky secondary alcohols such as 1-phenyl-1-dodecanol and 2-methyl-1-phenyl-1-propanol by simply using them in liquid carbon dioxide as a solvent. The effects of solvents, reaction pressure, and pre-treatment of the enzyme with liquid CO2on this acceleration phenomenon were also studied.
BORON FLUORIDE PROMOTED OPENING OF EPOXIDES BY ORGANOCOPPER AND CUPRATE REAGENTS
Alexakis, A.,Jachiet, D.,Normant, J. F.
, p. 5607 - 5620 (2007/10/02)
In the presence of BF3 the reaction rate of organocopper and cuprate reagents with poorly reactive epoxides is dramatically enhanced.Lithium organocuprates are the best choice among the various organocopper and cuprate reagents tested.Even the dimesityl cyanocuprate is able to react with cyclohexene oxide in excellent yield.No products of cationic rearrangements are observed.The reaction with various epoxides shows a complete stereochemical (pure anti opening) and regiochemical control (attack on the less hindered side of the epoxide).
