Enantioselective Reduction of Aliphatic Ketones Using Oxazaborolidine Catalyst Generated In Situ from Chiral Lactam Alcohol and Phenoxyborane

2009 ◽  
Vol 38 (7) ◽  
pp. 722-723 ◽  
Author(s):  
Yasuhiro Kawanami ◽  
Yudai Mikami ◽  
Katsuhiro Hoshino ◽  
Mikiko Suzue ◽  
Izumi Kajihara
Keyword(s):  
Enantioselective Reduction ◽  
Aliphatic Ketones

scholarly journals Practical Enantioselective Reduction of Ketones Using Oxazaborolidine Catalysts Generated In Situ from Chiral Lactam Alcohols

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2408 ◽  
Author(s):  
Yasuhiro Kawanami ◽  
Ryo Yanagita
Keyword(s):  
Practical Method ◽  
Enantioselective Reduction ◽  
Trifluoromethyl Ketones ◽  
Aliphatic Ketones ◽  
Borane Reduction ◽  
Absolute Stereochemistry ◽  
Reduction Of Ketones

Oxazaborolidine catalyst (CBS catalyst) has been extensively used for catalytic borane reduction with a predictable absolute stereochemistry and high enantioselectivity. However, the use of isolated CBS catalyst sometimes has the drawback of low reproducibility due to the aging of the CBS catalyst during storage. Therefore, we investigated a more reliable and practical method for the reduction of a variety of ketones including challenging substrates, primary aliphatic ketones, α,β-enones, and trifluoromethyl ketones. This review surveys the developments in borane reduction using oxazaborolidine catalysts generated in situ from chiral lactam alcohols and borane.

ChemInform Abstract: Enantioselective Reduction of Aliphatic Ketones Using Oxazaborolidine Catalyst Generated in situ from Chiral Lactam Alcohol and Phenoxyborane.

ChemInform ◽  
2009 ◽  
Vol 40 (47) ◽  
Author(s):  
Yasuhiro Kawanami ◽  
Yudai Mikami ◽  
Katsuhiro Hishino ◽  
Mikiko Suzue ◽  
Izumi Kajihara
Keyword(s):  
Enantioselective Reduction ◽  
Aliphatic Ketones

Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) HomoDimers as Lewis Acidic Superelectrophiles

2018 ◽  
Author(s):  
Haley Albright ◽  
Paul S. Riehl ◽  
Christopher C. McAtee ◽  
Jolene P. Reid ◽  
Jacob R. Ludwig ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Acid Activation ◽  
Lewis Acid Catalysts ◽  
Distinct Mode ◽  
Aliphatic Ketones ◽  
Carbon Carbon Bond ◽  
Metathesis Reactions ◽  
Acid Catalyzed

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>

The absorption of organic vapours by thin films of nitrocellulose

1954 ◽  
Vol 225 (1163) ◽  
pp. 478-504 ◽  
Keyword(s):  
Thin Films ◽  
Vapour Pressure ◽  
Alternative Explanation ◽  
Solubility Parameters ◽  
High Polymer ◽  
Pressure Data ◽  
Nitrate Esters ◽  
Aliphatic Ketones ◽  
Propyl Ketone

To check modem theories of high-polymer solutions measurements have been made of the effect of dissolved nitrocellulose on the vapour pressure of each of the following compounds: acetone, five other aliphatic ketones, dioxane, ethyl n -propyl ether, acetonitrile and nitromethane. All measurements were made at 20° C, the vapour pressures being directly observed and the mixtures analyzed by magnetic weighing in situ . The results for acetone confirm those by earlier workers, The isotherms for ethyl propyl ether, acetonitrile and nitromethane are satisfactorily described by the equation of Huggins (1942) with a different constant value of the parameter μ in each case. These μ values lead to a constant value of the ‘solubility parameter’ of nitrocellulose which is compatible with earlier data on the absorption of hydrocarbons and of diethyl ether. In contrast, the isotherms for the six ketones are not satisfactorily explained in that ( a ) the 11 values are not constant for any one isotherm , ( b ) the values predicted from ‘solubility parameters’ are incorrect. An alternative explanation is proposed, based on the Bronsted-Koefoed (1946) concept of ‘congruence’, which leads to an equation with one constant which is approximately the same for five of the ketones studied and for two ketones studied by previous workers. This equation is shown to be in agreement with previous work on (i) osm otic pressure, (ii) the absorption of carboxylate esters, (iii) the vapour pressure of acetone solutions of simple nitrate esters, and some further consequences are discussed. The results for dioxane and di- iso propyl ketone remain, however, anomalous on either interpretation. In an appendix vapour-pressure data are given for the compounds studied, and are compared with previous observations.

Practical Enantioselective Reduction of Ketones Using Oxazaborolidine Catalyst Generated in situ from Chiral Lactam Alcohols and Borane.

ChemInform ◽  
2004 ◽  
Vol 35 (5) ◽  
Author(s):  
Yasuhiro Kawanami ◽  
Shinichi Murao ◽  
Takahiko Ohga ◽  
Nobuyo Kobayashi
Keyword(s):  
Enantioselective Reduction ◽  
Reduction Of Ketones
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