This invention aims at providing a catalyst for producing an optically active aldehyde or an optically active ketone, which is an optically active carbonyl compound, by carrying out selective asymmetric hydrogenation of an α,β-unsaturated carbonyl compound, particularly a catalyst which is insoluble in a reaction mixture for obtaining optically active citronellal which is useful as a flavor or fragrance, by carrying out selective asymmetric hydrogenation of citral, geranial or neral; and a method for producing a corresponding optically active carbonyl compound. The invention relates to a catalyst for asymmetric hydrogenation of an α,β-unsaturated carbonyl compound, which comprises a powder of at least one metal selected from metals belonging to Group 8 to Group 10 of the Periodic Table, or a metal-supported substance in which at least one metal selected from metals belonging to Group 8 to Group 10 of the Periodic Table is supported on a support, an optically active cyclic nitrogen-containing compound and an acid.
An object of the present invention is to provide a method for manufacturing an optically active menthol having fewer steps, which generates less environmentally polluting waste because a catalytic reaction is involved in all of the steps, and is capable of saving a production cost. The present invention relates to a method for manufacturing an optically active menthol, including the following steps: A-1) asymmetrically hydrogenating at least one of geranial and neral to thereby obtain an optically active citronellal, B-1) conducting a ring-closure reaction of the optically active citronellal in the presence of an acid catalyst to thereby obtain an optically active isopulegol, and C-1) hydrogenating the optically active isopulegol to thereby obtain an optically active menthol.
Flexible and Chemoselective Oxidation of Amides to α-Keto Amides and α-Hydroxy Amides
作者:Aurélien de la Torre、Daniel Kaiser、Nuno Maulide
DOI:10.1021/jacs.7b02983
日期:2017.5.17
A suite of flexible and chemoselective methods for the transition-metal-free oxidation of amides to α-keto amides and α-hydroxy amides is presented. These highly valuable motifs are accessed in good to excellent yields and stereoselectivities with high functional group tolerance. The utility of the method is showcased by the formal synthesis of a potent histone deacetylase inhibitor.
Enantio‐ and Diastereoselective Nucleophilic Addition of
<i>N</i>
‐
<i>tert</i>
‐Butylhydrazones to Isoquinolinium Ions through Anion‐Binding Catalysis
作者:Esteban Matador、Javier Iglesias‐Sigüenza、David Monge、Pedro Merino、Rosario Fernández、José M. Lassaletta
DOI:10.1002/anie.202012861
日期:2021.3
A highly enantio‐ and diastereoselective thiourea‐catalyzed dearomatization of isoquinolines employing N‐tert‐butylhydrazones as neutral α‐azo carbanions and masked acyl anion equivalents has been developed. Experimental and computational data supports the generation of highly ordered complexes wherein the chloride behaves as a template for the catalyst, the hydrazone reagent, and the isoquinolinium
Novel Asymmetric Formylation of Aromatic Compounds: Enantioselective Synthesis of Formyl 7,8-Dipropyltetrathia[7]helicenes
作者:Julien Doulcet、G. Richard Stephenson
DOI:10.1002/chem.201501627
日期:2015.9.14
Asymmetric formylation of aromatic compounds is virtually unexplored. We report the synthesis and evaluation of a library including 20 new chiral formamides in the kinetic resolution of 7,8‐dipropyltetrathia[7]helicene, affording the corresponding formyl‐ or diformylhelicenes in up to 73 % ee, making enantiopure compounds available by recrystallisation. With the N,N‐disubstituted formamides used in