Woo-Jin Yoo’s research while affiliated with The University of Tokyo and other places

... [27] In fact, triethylamine (Et 3 N), 1,4-Diazabicyclo[2.2.2]octane (DABOC), 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) were used as achiral organosuperbases in many reactions. In recent decade, several types of chiral organosuperbases [28,29] including amidine, [30][31][32] guanidine, [33][34][35][36][37][38][39][40][41] cyclopropenimine, [42][43][44][45][46][47] iminophosphorane, [48][49][50][51][52][53][54][55][56] and azaphosphatrane [57][58][59][60] have been developed and used as catalysts for direct deprotonation of substrates with high pK a values in asymmetric Michael reaction, Mannich reaction, amination, oxidation, aldol reaction and [3 + 2] cycloaddition. Benzophenone-protected glycine t-butyl ester 1 a bearing not only high pK a but also bulky group was regarded as a challenging substrate for asymmetric Michael addition. ...

Reference:

Chiral Cyclopropenimine‐catalyzed Asymmetric Michael Addition of Bulky Glycine Imine to α,β‐Unsaturated Isoxazoles

... [9] Although there are few methods for constructing butenolides from CO 2 , they usually rely on the carboxylation of vinyl metal intermediates prepared in advance from propargyl alcohols. [10][11][12] The multi-step procedures and the use of stoichiometric amount of organometallic reagents are the shortages of the protocols. For example, in 2020 Yoo et al. reported the synthesis of butenolides through a sequential hydroalumination of propargyl alcohols/ carboxylation with CO 2 /acid-mediated intramolecular condensation procedure (Scheme 1d). ...

Reference:

Palladium‐Catalyzed Carbonylative Cyclization of Propargyl Alcohols with CO2: a Straightforward Route to Butenolides

... There are a variety of synthetic approaches that have been used to prepare CAPE and CAPA analogues, but the most common include the ester or amide coupling of caffeic acid derivatives or the Wittig olefination of appropriate benzaldehydes [16]. Continuous flow methods offer several advantages to traditional batch methods for the synthesis of biologically active compounds in terms of safety, sustainability, and efficiency [17]. Specifically, Wittig olefination carried out in flow reactors has been used to prepare cinnamic ester derivatives [18] and cinnamides [19,20]. ...

Reference:

Flow and On-Water Synthesis and Cancer Cell Cytotoxicity of Caffeic Acid Phenethyl Amide (CAPA) Derivatives

... We have previously reported on the use of chiral Ni species with a single-site surface on mesoporous silica MCM-41 for enantioselective 1,4-addition reactions catalyzed by the chiral Ni sites. [6] The active Ni catalyst on the surface was constructed by a simple surface reaction between the NiI 2 -2L1 complex [7] and the silica surface of neutral MCM-41, giving L1ligated Ni-silicate (NiÀ L1@MCM-41), the structure of which was revealed by extended X-ray absorption fine structure (EXAFS) analyses. The obtained catalyst exhibited several specific properties that were not apparent in its homogeneous counterpart. ...

Reference:

Continuous‐Flow Enantioselective 1,4‐Addition Reactions of Malonates with Nitroolefins on Ni‐Supported Mesoporous Silica Materials with Co‐feeding of a Chiral Ligand

... Aza-pinacol coupling of imines 1 offers a convenient approach for the synthesis of tetrasubstituted ethanediamines 2 ( Figure 1a), which are used, for example, as chiral ligands in catalysis. 1,2 Zn dust, 3,4 mischmetall, 5 Na, 6 and TiC 4 /amalgamated Mg 7 have been investigated as reductants. On the other hand, aza-pinacol coupling of imines is enabled by photoredox catalysis and sensitizers, such as Ir−polypyridine complex, 8 heterogeneous CdS semiconductor, 9 or transition metal-free organic dyes, Nphenylphenothiazine, 10 diphenyldibenzocarbazole, 11 and perylene. ...

Reference:

Assignment of the Crystal Structure to the Aza -Pinacol Coupling Product by X-ray Diffraction and Density Functional Theory Modeling

... Along this line, the Yoo laboratory reported the synthesis of aryl carboxylic acids 44 by a regioselective Cu-catalyzed F-mediated carboxylation of [2-(hydroxymethyl)phenyl]dimethyl(aryl)silanes 43 with CO 2 (1 atm) under mild conditions (Scheme 25) [36]. Regarding the influence of substituents, the substrates bearing electron-withdrawing groups led to higher yields compared to those bearing electron-donating groups. ...

Reference:

Incorporation of CO2 into organosilicon compounds via C Si bond cleavage

... Further, for late-stage modifications, gem-difluoro alkenes can be converted to diverse organofluorine moieties [37,216] including trifluoromethyl [217][218][219], difluoromethyl [220], mono-fluoro alkenyl [221,222], and difluoro-methylenyl [223] groups. The 2,2-difluorovinyl benzoates (BzO-DFs) are valuable constituents for the production of a variety of gemdifluoro alkenes and gem difluoroenol ethers via nucleophilic catalyzed arylation and alkylation. ...

Reference:

Stereospecific/stereoselective Nickel catalyzed reductive cross-coupling: An efficient tool for the synthesis of biological active targeted molecules

... [8,9] It was shown that such alkenes can be 1,2-difunctionalized using an external fluoride source to construct the CF 3 -moiety for the expedient synthesis of CF 3 -containing compounds through radical, anionic or cationic pathways. [10][11][12][13][14][15] In this context, the groups of Hu, [10] Feng, [11] Loh, [11b,c] Malcolmson, [12] Kobayashi [13] and Jiang [14] contributed with elegant studies that document the synthetic potential of gem-difluoroalkenes as substrates for the preparation of 1,1,1-trifluoro-2arylalkane derivatives. Considering the abundant reactivity of gem-difluoroalkenes, we aimed to explore atom-economical carbofluorination reactions that combine C À F bond cleavage and formation in a single transformation to avoid the necessity of an additional fluoride source. ...

Reference:

Cooperative Photoredox and N‐Heterocyclic Carbene Catalyzed Fluoroaroylation for the Synthesis of α‐Trifluoromethyl‐Substituted Ketones

... However, in these ways, a large amount of waste is also usually generated. Some heterogeneous catalysts were also described for Friedel-Crafts acylation [15][16][17] in batch mode or in a continuous process, but, to the best of our knowledge, the continuous acylation of 1,3-benzodioxole was not studied in detail. ...

Reference:

Improved Process for the Continuous Acylation of 1,3-Benzodioxole

... 20,21 Various optical-switching molecules, including spiropyran, diarylbenzene, and azobenzene, were found successively. [22][23][24][25] More importantly, photo-response molecules could precisely control the target organism bioactivity, 26 reduce drug resistance, 27 and avoid side effects, 28 which were superior to traditional drugs. 29 For instance, azobenzene showed an unprecedented photosensitive property and thus has wide applications in the fields of photopharmacology, 30 surfactants, 31 liquid crystals, 32 energy storage compounds, 33 biomolecules, 34 supramolecular selfassembled polymers, 35 and nanoparticles. ...

Reference:

Engineering the novel azobenzene‐based molecular photoswitches for suppressing bacterial infection through dynamic regulation of biofilm formation