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Iwaki, Japan

Kumagai J.,Muroran Institute of Technology | Otsuki T.,Muroran Institute of Technology | Subba Reddy U.V.,Muroran Institute of Technology | Kohari Y.,Muroran Institute of Technology | And 7 more authors.
Tetrahedron Asymmetry | Year: 2015

Simple chiral triethylsilyl-amino alcohol organocatalysts containing a bulky triethylsilyl group on the oxygen atom at the γ-position were designed and synthesized as new organocatalysts for enantioselective Diels-Alder reactions of anthrones with maleimides to produce chiral hydroanthracene Diels-Alder adducts in up to 99% yield and with up to 94% ee. © 2015 Elsevier Ltd. All rights reserved. Source


Sakuta Y.,Muroran Institute of Technology | Kohari Y.,Muroran Institute of Technology | Hutabarat N.D.M.R.,Muroran Institute of Technology | Uwai K.,Muroran Institute of Technology | And 8 more authors.
Heterocycles | Year: 2012

The enantioselective Diels-Alder reactions of 1,2-dihydropyridines with acroleins using a chiral primary amino silyl ether organocatalyst afforded chiral isoquinuclidines with good chemical yields and excellent enantioselectivities (up to 70% and up to 99% ee). © 2012 The Japan Institute of Heterocyclic Chemistry. Source


Uwai K.,Muroran Institute of Technology | Okuyama Y.,Tohoku Pharmaceutical University | Nakano H.,Muroran Institute of Technology | Furukawa K.,Tohoku Pharmaceutical University | And 6 more authors.
Biocatalysis and Agricultural Biotechnology | Year: 2014

The biotransformation of organic compounds using the larvae of the Japanese rhinoceros beetle (Allomyrina dichotoma) as a biocatalyst is described. When phenyl alkanediones were administered by mouth (p.o) or subcutaneous injection (s.c) to the beetle, asymmetric reduction occurred to yield the corresponding diols in varying optical yields: 1-phenyl-1,2-propandione or 1-phenyl-1,3-butanedione reduced to (1R,2S)- and (1S,2S)-1,2-phenylpropanediols in high optical yields or (1R,3S)- and (1R,3R)-1-phenyl-1,3-butanediols in low to high optical yields, respectively. By administrating 1-phenyl-1-propanone, 1-phenyl-1-butanone or 4-phenyl-2-butanone, redox reactions occurred to give 1-phenyl-1,2-propanediols or 1-phenyl-1,3-butanediols in lower optical yields. The administrations of β-ionone and cinnamyl chloride resulted in regioselective allylic oxidations producing enone and cinnamic acid, respectively. However, when (R)-(-)-carvone was administered, regiospecific dihydroxylation at the isopropenyl group occurred to give (4R,8R)- and (4R,8S)-8,9-dihydroxy-8,9-dihydrocarvone as diastereoisomers. These results appear to demonstrate similar reaction tendency with the case of a microorganism. It is possible that these reactions were due in part to bacteria in the intestine of the larva: however, regio- and stereoselectivities of the reactions were sometimes unique. Thus, it is supposed that these biotransformations were accomplished by the ensemble of the larva's own enzymes with several bacteria. The results obtained in this study might show the possibility of using such enzymes derived from insects, including beetle larvae, as a biocatalyst. © 2014 Elsevier Ltd. Source


Sano K.,Muroran Institute of Technology | Kohari Y.,Muroran Institute of Technology | Nakano H.,Muroran Institute of Technology | Seki C.,Muroran Institute of Technology | And 4 more authors.
Synthetic Communications | Year: 2016

Synthesis of bicyclic compounds was achieved via a lipase-catalyzed, stereoselective, domino Michael-aldol reaction of 2-methyl-1,3-cycloalkanedione and methyl vinyl ketone. Appropriate reaction conditions, including the type of enzyme, solvent, and temperature, were determined. In addition, the effects of solvent polarity and addtives were investigated. The reaction proceeded in the presence of lipase AS in a solution of 20% acetone in dimethylsulfoxide (DMSO) at 10 °C for 8 days, followed by the addition of p-toluenesulfonic acid (TsOH) to afford bicyclic compounds in 51-83% yields with moderate stereoselectivity. Although this domino Michael-aldol reaction showed only moderate stereoselectivity, even with the acid-supported enhancement of the reaction, these results represent potential new applications for lipase. © 2016 Taylor & Francis Group, LLC. Source


Otsuki T.,Muroran Institute of Technology | Kumagai J.,Muroran Institute of Technology | Kohari Y.,Muroran Institute of Technology | Okuyama Y.,Tohoku Pharmaceutical University | And 12 more authors.
European Journal of Organic Chemistry | Year: 2015

The catalytic activity of a simple amino alcohol that contains a bulky super silyl group [i.e., tris(trimethylsilyl)silyl (TTMSS)] bonded to the oxygen atom at the γ-position along with a primary amine moiety was examined in the enantioselective 1,3-dipolar cycloaddition of nitrones to α,β-unsaturated aldehydes. The organocatalyst successfully provided optically active isoxazolidines in good chemical yields (up to 86 %) with excellent diastereoselectivities (endo/exo, up to 96:4) and enantioselectivities (up to 97 % ee). Furthermore, the obtained isoxazolidines were easily converted into γ-amino diols that contain three contiguous stereogenic centers. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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