Chiral Quaternary Phosphonium Salts Research Articles

Synthesis, crystal structure, and biological activity of menthol-based chiral quaternary phosphonium salts (CQPSs)

Synthesis, crystal structure, and biological activity of menthol-based chiral quaternary phosphonium salts (CQPSs)

Enantioselective Michael Addition Reactions to Construct SCF3‐containing Stereocenter Catalyzed by Chiral Quaternary Phosphonium Salts

AbstractThe trifluoromethylthio group is significant in drug design for its high stability, electronegativity, and lipophilicity. Herein, a series of indenone structures containing the SCF3 group and an adjacent chiral quaternary stereocenter were synthesized by an asymmetric Michael addition reaction using an ion pair catalyst derived from amino acids. The desired products were obtained in excellent yields (up to 98%) and good to high stereoselectivities (up to 97% ee and >20:1 dr).magnified image

Enantioselective Vinylogous Mannich‐Type Reactions to Construct CF3S‐Containing Stereocenters Catalysed by Chiral Quaternary Phosphonium Salts

AbstractA series of benzyl trifluoromethyl sulphides bearing a nitro group were utilized as CF3S‐containing building blocks to construct chiral CF3S‐containing molecules via enantioselective vinylogous Mannich‐type reactions. In such reactions, high yields and enantioselectivities were obtained using chiral quaternary phosphonium salts derived from amino acids. Moreover, a chiral cyclic urea bearing the CF3S moiety was obtained from further transformation of the product.magnified image

Highly Enantioselective Conjugate Addition of Glycine Imines to Activated Alkenes Catalyzed by Amino‐Acid‐Derived Chiral Phosphonium Salts

Chiral quaternary phosphonium salts derived from amino acids were readily prepared and employed as phase‐transfer catalysts for the highly enantioselective conjugate addition of glycine imines to various activated alkenes, including chalcones, acrylates, and vinyl ketones.

ChemInform Abstract: Chiral Quaternary Phosphonium Salts as Phase‐Transfer Catalysts for Environmentally Benign Asymmetric Transformations

AbstractReview: [37 refs.

Chiral quaternary phosphonium salts as phase-transfer catalysts for environmentally benign asymmetric transformations

The development of chiral quaternary phosphonium salt catalysts for environmentally benign asymmetric phase-transfer reactions is summarized.

ChemInform Abstract: Enantioselective Desymmetrization of meso‐Aziridines with Aromatic Thiols Catalyzed by Chiral Bifunctional Quaternary Phosphonium Salts Derived from α‐Amino Acids.

Desymmetrization of meso-aziridines with aromatic thiols was realized by using α-amino acids-derived chiral quaternary phosphonium salts catalysts to provide chiral β-amino sulfides with high yields (up to 99%) and in moderate enantioselectivities (up to 70%).

Enantioselective desymmetrization of meso-aziridines with aromatic thiols catalyzed by chiral bifunctional quaternary phosphonium salts derived from α-amino acids

Desymmetrization of meso-aziridines with aromatic thiols was realized by using α-amino acids-derived chiral quaternary phosphonium salts catalysts to provide chiral β-amino sulfides with high yields (up to 99%) and in moderate enantioselectivities (up to 70%).

ChemInform Abstract: Efficient Approach for the Design of Effective Chiral Quaternary Phosphonium Salts in Asymmetric Conjugate Additions.

AbstractVarious phosphonium bromide catalysts are presented, one of them proves to be an efficient promoter for asymmetric conjugate additions under base‐free phase transfer conditions with low catalyst loading.

Efficient approach for the design of effective chiral quaternary phosphonium salts in asymmetric conjugate additions

An efficient approach for the design of chiral quaternary phosphonium bromides as chiral phase-transfer catalysts was demonstrated. A catalyst library of phosphonium salts with various structures was readily constructed using commercially available chiral phosphines as catalyst precursors, and an optimized catalyst was successfully applied to highly enantioselective conjugate additions under base-free phase-transfer conditions with low catalyst loading.

ChemInform Abstract: Chiral Quaternary Phosphonium Salts: A New Class of Organocatalysts

AbstractReview: 50 refs.

Chiral quaternary phosphonium salts: a new class of organocatalysts

Phase-transfer catalysis has widely been used as a prime synthetic tool for both laboratory and industrial processes. During the last twenty years, asymmetric phase-transfer catalysis using chiral organocatalysts has attracted widespread interest. However, the scope of chiral phase-transfer catalysis has been limited mostly to the quaternary ammonium salts. As an emerging area, the recent developments in the application of quaternary phosphonium salts as chiral phase-transfer catalysts are discussed in this article.

Synthesis of Enantiopure 1‐r‐Alkyl‐2‐c,5‐t‐Diphenylphospholanes and Phospholanium Salts through Direct Alkylation of Phospholane

AbstractChiral enantiopure 1‐alkyl‐2,5‐diphenylphospholanium salts were obtained in one step through alkylation of phospholane with alkyl triflates. The resulting air‐stable phosphonium salts are electron‐rich trialkylphosphane precursor ligands for transition metals, and they offer a convenient route toward chiral quaternary phosphonium salts as phase‐transfer agents.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

ChemInform Abstract: Synthesis of Novel Chiral Quaternary Phosphonium Salts with a Multiple Hydrogen‐Bonding Site, and Their Application to Asymmetric Phase‐Transfer Alkylation.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of novel chiral quaternary phosphonium salts with a multiple hydrogen-bonding site, and their application to asymmetric phase-transfer alkylation

Chiral phosphonium salts having two NH and two OH groups as hydrogen-bond donors have been synthesized as novel phase-transfer catalysts, and used for asymmetric alkylation of β-keto esters to give the corresponding products with up to 50% ee.

Determination of the optical purity of chiral quaternary phosphonium salts by differential scanning calorimetry

Determination of the optical purity of chiral quaternary phosphonium salts by differential scanning calorimetry