Desymmetrization of σ-Symmetric Biphenyl-2,6-diyl Diacetate Derivatives by Lipase-Catalyzed Hydrolysis: Unexpected Effect of C(3′)-Substituent on the Enantiotopic Group Selectivity

Ochiai, Mio; Akisawa, Yuki; Kajiyama, Daichi; Matsumoto, Takashi

doi:10.1055/s-0037-1611701

Cited by 10 publications

(1 citation statement)

References 2 publications

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“…Moreover, some types are also used as materials in dye technology, , sensor, , and organic light-emitting diodes (OLEDs) − due to the conjugation and heteroring in their structures, ensuring optical and electrochemical properties. In addition to these activities, the most noticeable biological activities of thioxanthenes are their use as drugs in many neurological diseases. − …”

Section: Introductionmentioning

confidence: 99%

Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Deniz,

Yıldız,

Başpınar Küçük

2024

ACS Omega

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In this study, a series of halogen-substituted thioxanthenes were synthesized because the most important and biologically active derivatives of xanthenes are thioxanthenes. In order to obtain new thioxanthene derivatives, first, the starting molecules were synthesized by the appropriate reaction methods in two steps. The intramolecular Friedel−Crafts alkylation (FCA) method was used to convert the prepared three aromatic substituted starting alcohol compounds to their corresponding thioxanthenes by cyclization. For the intramolecular FCA reaction of secondary alcohols, which are the starting compounds (1a−1t), organic Bro̷ nsted acids, which require more innovative, easier, and suitable reaction conditions, were used instead of halide reagents with corrosive effects as classical FCA catalysts. Trifluoroacetic acid was determined to be the organocatalyst with the best yield. Therefore, some original 9-aryl/alkyl thioxanthene derivatives (2a−2t) were synthesized using the optimized FCA method. In addition, a new sulfone derivative of thioxanthene 3i was prepared by performing the oxidation reaction with one of the obtained new thioxanthene 2i. Thioxanthenes and their derivatives are important heterocyclic structures that contain pharmacologically valuable sulfur and are used in the treatment of psychotic diseases such as Alzheimer's or schizophrenia, as well as a number of potent biological activities.

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Section: Introductionmentioning

confidence: 99%

Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Deniz,

Yıldız,

Başpınar Küçük

2024

ACS Omega

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Atroposelective Total Synthesis of (+)‐Isokotanin A via Combined Metal and Enzyme Catalysis

Christine Ganardi,

Greb,

Henßen

et al. 2023

Adv Synth Catal

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In this report a new atroposelective total synthesis of (+) isokotanin A is described. The combination of metal‐ and enzyme catalysis facilitates a scalable route towards the key axially chiral 2,2′ biphenol building block. We established a one‐pot Miyaura‐Suzuki homocoupling towards the tetra‐ortho‐substituted biphenol on a decagram scale, applying Buchwald’s precatalyst PdG4SPhos and SPhos in low loadings. Next, an enzymatic kinetic resolution method was achieved by utilizing commercially available Candida rugosa lipase for catalyzing the enantioselective hydrolysis of biphenyl dipropionate. The enantiomerically pure tetra‐ortho‐substituted biphenol was converted in 8 steps to the natural product.

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Isothiourea‐Catalyzed Atropselective Acylation of Biaryl Phenols via Sequential Desymmetrization/Kinetic Resolution

et al. 2020

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Axially chiral phenols are attractive targets in organic synthesis. This motif is central to many natural products and widely used as precursors to, or directly, as chiral ligands and catalysts. Despite their utility few simple catalytic methods are available for their synthesis in high enantiopurity. Herein the atropselective acylation of a range of symmetric biaryl diols is investigated using isothiourea catalysis. Studies on a model biaryl diol substrate shows that the high product er observed in the process is a result of two successive enantioselective reactions consisting of an initial enantioselective desymmetrization coupled with a second chiroablative kinetic resolution. Extension of this process to a range of substrates, including a challenging tetraorthosubstituted biaryl diol, led to highly enantioenriched products (14 examples, up to 98:2 er), with either HyperBTM or BTM identified as the optimal catalyst depending upon the substitution pattern within the substrate. Computation has been used to understand the factors that lead to high enantiocontrol in this process, with maintenance of planarity to maximize a 1,5‐S⋅⋅⋅O interaction within the key acyl ammonium intermediate identified as the major feature that determines atropselective acylation and thus product enantioselectivity.

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Desymmetrization of σ-Symmetric Biphenyl-2,6-diyl Diacetate Derivatives by Lipase-Catalyzed Hydrolysis: Unexpected Effect of C(3′)-Substituent on the Enantiotopic Group Selectivity

Cited by 10 publications

References 2 publications

Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Atroposelective Total Synthesis of (+)‐Isokotanin A via Combined Metal and Enzyme Catalysis

Isothiourea‐Catalyzed Atropselective Acylation of Biaryl Phenols via Sequential Desymmetrization/Kinetic Resolution

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