scholarly journals Ligand-redox assisted nickel catalysis toward stereoselective synthesis of (n+1)-membered cycloalkanes from 1,n-diols with methyl ketones

2021 ◽  
Author(s):  
Amreen K Bains ◽  
Abhishek Kundu ◽  
Debashis Adhikari ◽  
Debabrata Maiti
Keyword(s):  
Nickel Catalyst ◽  
Methyl Ketone ◽  
Stereoselective Synthesis ◽  
Nickel Catalysis ◽  
Methyl Ketones

A well-defined, bench-stable nickel catalyst is presented here, that can conduct double alkylation of a methyl ketone to realize a wide variety of cycloalkanes. The performance of the catalyst hinges...

Chemistry of the Podocarpaceae. XXXIV. Some oxidation products of (13R)-Labda-8(17),14-dien-13-ol (Manool)

1971 ◽  
Vol 24 (11) ◽  
pp. 2365 ◽  
Author(s):  
RC Cambie ◽  
KN Joblin ◽  
AF Preston
Keyword(s):  
Nucleophilic Substitution ◽  
Potassium Permanganate ◽  
Hydroxy Acid ◽  
Methyl Ketone ◽  
Major Product ◽  
Oxidation Products ◽  
Lithium Aluminium Hydride ◽  
Methyl Ketones ◽  
Sodium Dichromate ◽  
Lithium Aluminium

Some products from the oxidation of manool (3) are examined. Potassium permanganate gives, inter alia, the hitherto unreported compound (16) while sodium dichromate gives the methyl ketone (5) and, as the major product, a mixture of (Z)- and (E)-α,β-unsaturated aldehydes (21). Hypoiodite oxidation of the methyl ketone (5) gives the α-hydroxy acid (26) in addition to the expected acid (6). Products of nucleophilic substitution have also been obtained from the hypoiodite oxidation of the methyl ketones (9) and (37). Peracid oxidation of the methyl ketone (5) gives the epoxy acetate (41) which, on reduction with lithium aluminium hydride, affords the diol (7), from which the odoriferous oxide (30) can be prepared. Oxidations leading to formation of the dione (10) are investigated.

Stereoselective synthesis of a Podophyllum lignan core by intramolecular reductive nickel-catalysis

2018 ◽  
Vol 54 (16) ◽  
pp. 2040-2043 ◽  
Author(s):  
Jian Xiao ◽  
Xiao-Wei Cong ◽  
Gui-Zhen Yang ◽  
Ya-Wen Wang ◽  
Yu Peng
Keyword(s):  
Stereoselective Synthesis ◽  
Nickel Catalysis

Ni-catalyzed intramolecular coupling for a stereodivergent construction of a THN[2,3-c]furan core embedded in bioactive Podophyllum lignans, is developed.

Stereoselective synthesis of α-methyl and α-alkyl ketones from esters and alkenesviacyclopropanol intermediates

2018 ◽  
Vol 54 (22) ◽  
pp. 2800-2803 ◽  
Author(s):  
Maryia V. Barysevich ◽  
Volha V. Kazlova ◽  
Aliaksandr G. Kukel ◽  
Aliaksandra I. Liubina ◽  
Alaksiej L. Hurski ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Methyl Ketones

Diastereoselective Kulinkovich hydroxycyclopropanation of alkenes with esters and a protocol for the isomerization of chiral cyclopropanols to α-methyl ketones have been developed.

scholarly journals Bimetallic Cooperativity with a 2-Phosphinoimidazole-Derived Pd(II) Dimer Enables Naphthalene Synthesis via dimeric Pd(III) Catalysis

2020 ◽  
Author(s):  
Chloe C. Ence ◽  
S. Hadi Nazari ◽  
Mariur Rodriguez Moreno ◽  
Manase F. Matu ◽  
Samantha G. Kulka ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Dft Calculations ◽  
Oxidation State ◽  
Methyl Ketone ◽  
Methyl Ketones ◽  
Mechanistic Studies ◽  
High Oxidation State ◽  
Pd Catalysts ◽  
Silver Triflate ◽  
High Oxidation

We report the synthesis of bimetallic Pd(I) and Pd(II) complexes scaffolded on bidentate 2-phosphinoimidazole ligands. These complexes display unique catalytic activity and enable the expeditious formation of 1,3-disubstituted naphthalenes via an unprecedented coupling of aryl iodides and methyl ketones in the presence of silver triflate. Excellent substrate scope for naphthalene formation is also demonstrated. Mechanistic studies suggest that the transformation proceeds via Pd-catalyzed arylation of a methyl ketone, followed by cyclization with a second equivalent of ketone. Importantly, this ketone arylation processes occurs under oxidizing conditions, suggesting involvement of higher oxidation state dimeric Pd catalysts. Based on experiments and DFT calculations, we propose a mechanism involving high oxidation state Pd(III) bimetallic catalysis. These new bimetallic complexes possess reactivity that is not seen with monometallic Pd catalysts and we confirm the importance of the palladium catalyst for both arylation and cyclization for naphthalene formation.

scholarly journals Degradation of Alkyl Methyl Ketones by Pseudomonas veronii MEK700

2007 ◽  
Vol 189 (10) ◽  
pp. 3759-3767 ◽  
Author(s):  
Christina Onaca ◽  
Martin Kieninger ◽  
Karl-H. Engesser ◽  
Josef Altenbuchner
Keyword(s):  
Ethyl Acetate ◽  
Methyl Ketone ◽  
Glycogen Synthase ◽  
Short Chain ◽  
Insertion Mutant ◽  
Methyl Ketones ◽  
Monooxygenase Activity ◽  
Transposon Insertion ◽  
Waste Air ◽  
Pseudomonas Veronii

ABSTRACT Pseudomonas veronii MEK700 was isolated from a biotrickling filter cleaning 2-butanone-loaded waste air. The strain is able to grow on 2-butanone and 2-hexanol. The genes for degradation of short chain alkyl methyl ketones were identified by transposon mutagenesis using a newly designed transposon, mini-Tn5495, and cloned in Escherichia coli. DNA sequence analysis of a 15-kb fragment revealed three genes involved in methyl ketone degradation. The deduced amino acid sequence of the first gene, mekA, had high similarity to Baeyer-Villiger monooxygenases; the protein of the second gene, mekB, had similarity to homoserine acetyltransferases; the third gene, mekR, encoded a putative transcriptional activator of the AraC/XylS family. The three genes were located between two gene groups: one comprising a putative phosphoenolpyruvate synthase and glycogen synthase, and the other eight genes for the subunits of an ATPase. Inactivation of mekA and mekB by insertion of the mini-transposon abolished growth of P. veronii MEK700 on 2-butanone and 2-hexanol. The involvement of mekR in methyl ketone degradation was observed by heterologous expression of mekA and mekB in Pseudomonas putida. A fragment containing mekA and mekB on a plasmid was not sufficient to allow P. putida KT2440 to grow on 2-butanone. Not until all three genes were assembled in the recombinant P. putida was it able to use 2-butanone as carbon source. The Baeyer-Villiger monooxygenase activity of MekA was clearly demonstrated by incubating a mekB transposon insertion mutant of P. veronii with 2-butanone. Hereby, ethyl acetate was accumulated. To our knowledge, this is the first time that ethyl acetate by gas chromatographic analysis has been definitely demonstrated to be an intermediate of MEK degradation. The mekB-encoded protein was heterologously expressed in E. coli and purified by immobilized metal affinity chromatography. The protein exhibited high esterase activity towards short chain esters like ethyl acetate and 4-nitrophenyl acetate.

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