The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform
Nina Schützenmeister - One of the best experts on this subject based on the ideXlab platform.
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β selective one pot synthesis of acyl c glycosides via corey Seebach Umpolung reaction
Synlett, 2019Co-Authors: Jacob G Boehlich, Nina SchützenmeisterAbstract:C-Glycosides are commonly used as carbohydrate mimics in drug development due to their stability against enzymatic and chemical hydrolysis. In this Synpacts article we elaborate on our fast and efficient β-selective approach towards protected and unprotected acyl glycosides. Application of a Corey–Seebach Umpolung reaction enables the exclusive formation of the β-anomer of aromatic acyl-C-glycosides in good to excellent yields. 1 Introduction 2 C-Glycosylation of Benzylated Glycosyl Donors 3 C-Glycosylation of Silylated Glycosyl Donors 4 Conclusion
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β-Selective One-Pot Synthesis of Acyl-C-Glycosides via Corey–Seebach Umpolung Reaction
Synlett, 2019Co-Authors: G. Jacob Boehlich, Nina SchützenmeisterAbstract:C-Glycosides are commonly used as carbohydrate mimics in drug development due to their stability against enzymatic and chemical hydrolysis. In this Synpacts article we elaborate on our fast and efficient β-selective approach towards protected and unprotected acyl glycosides. Application of a Corey–Seebach Umpolung reaction enables the exclusive formation of the β-anomer of aromatic acyl-C-glycosides in good to excellent yields. 1 Introduction 2 C-Glycosylation of Benzylated Glycosyl Donors 3 C-Glycosylation of Silylated Glycosyl Donors 4 Conclusion
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β-Selective C-Glycosylation and its Application in the Synthesis of Scleropentaside A.
Angewandte Chemie (International ed. in English), 2019Co-Authors: G. Jacob Boehlich, Nina SchützenmeisterAbstract:C-Glycosides are carbohydrates that bear a C-C bond to an aglycon at the anomeric center. Due to their high stability towards chemical and enzymatic hydrolysis, these compounds are widely used as carbohydrate mimics in drug development. Herein, we report a general and exclusively β-selective method for the synthesis of a naturally abundant acyl-C-glycosidic structural motif first found in the scleropentaside natural product family. A Corey-Seebach Umpolung reaction as the key step in the synthesis of scleropentaside A and analogues enables the β-selective construction of the anomeric C-C bond starting from unprotected carbohydrates in only four steps. The one-pot approach is highly atom-efficient and avoids the use of toxic heavy metals.
G. Jacob Boehlich - One of the best experts on this subject based on the ideXlab platform.
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β-Selective One-Pot Synthesis of Acyl-C-Glycosides via Corey–Seebach Umpolung Reaction
Synlett, 2019Co-Authors: G. Jacob Boehlich, Nina SchützenmeisterAbstract:C-Glycosides are commonly used as carbohydrate mimics in drug development due to their stability against enzymatic and chemical hydrolysis. In this Synpacts article we elaborate on our fast and efficient β-selective approach towards protected and unprotected acyl glycosides. Application of a Corey–Seebach Umpolung reaction enables the exclusive formation of the β-anomer of aromatic acyl-C-glycosides in good to excellent yields. 1 Introduction 2 C-Glycosylation of Benzylated Glycosyl Donors 3 C-Glycosylation of Silylated Glycosyl Donors 4 Conclusion
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β-Selective C-Glycosylation and its Application in the Synthesis of Scleropentaside A.
Angewandte Chemie (International ed. in English), 2019Co-Authors: G. Jacob Boehlich, Nina SchützenmeisterAbstract:C-Glycosides are carbohydrates that bear a C-C bond to an aglycon at the anomeric center. Due to their high stability towards chemical and enzymatic hydrolysis, these compounds are widely used as carbohydrate mimics in drug development. Herein, we report a general and exclusively β-selective method for the synthesis of a naturally abundant acyl-C-glycosidic structural motif first found in the scleropentaside natural product family. A Corey-Seebach Umpolung reaction as the key step in the synthesis of scleropentaside A and analogues enables the β-selective construction of the anomeric C-C bond starting from unprotected carbohydrates in only four steps. The one-pot approach is highly atom-efficient and avoids the use of toxic heavy metals.
Jacob G Boehlich - One of the best experts on this subject based on the ideXlab platform.
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β selective one pot synthesis of acyl c glycosides via corey Seebach Umpolung reaction
Synlett, 2019Co-Authors: Jacob G Boehlich, Nina SchützenmeisterAbstract:C-Glycosides are commonly used as carbohydrate mimics in drug development due to their stability against enzymatic and chemical hydrolysis. In this Synpacts article we elaborate on our fast and efficient β-selective approach towards protected and unprotected acyl glycosides. Application of a Corey–Seebach Umpolung reaction enables the exclusive formation of the β-anomer of aromatic acyl-C-glycosides in good to excellent yields. 1 Introduction 2 C-Glycosylation of Benzylated Glycosyl Donors 3 C-Glycosylation of Silylated Glycosyl Donors 4 Conclusion
Heyao Shi - One of the best experts on this subject based on the ideXlab platform.
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Total synthesis of (â)-himalensine A and development of novel C(sp3)-H functionalisation reactions
2018Co-Authors: Heyao ShiAbstract:This thesis describes the 22-step enantioselective total synthesis of (-)-himalensine A, and the Cp*RhIII catalysed amidation of unactivated C(sp3)-H bonds utilising dithianes or imines as directing groups. Chapter 1 introduces the calyciphylline A-type Daphniphyllum alkaloids, their biosynthetic origin and himalensine A as one family member. Current published syntheses of these alkaloids are also highlighted as well as previous work conducted on this project. Chapter 2 focuses on the route development towards the ABCD tetracyclic core. Optimisation of the key enantioselective organocatalytic IMDAF cascade enabled the synthesis of large quantities of the tricyclic core. After elaboration to a key cycloisomerisation precursor, a reductive radical cascade was developed to close the B ring. Finally, a highly diastereoselective low-pressure hydrogenation delivered the completed tetracyclic core. Chapter 3 describes the route from the tetracyclic core through the end-game to access himalensine A. A pyridine and molecular oxygen mediated elimination/C-H oxidation was developed to access an enedione intermediate with the correct oxidation level and chemical handle required to complete the final ring. The E ring was furnished via a Stetter cyclisation and final chemoselective lactam reduction delivered the natural product. Chapter 4 summarises C-H functionalisation within the context of C-N bond forming reactions. A focus is placed on rhodium, itâs ability for directed C-H amination/amidation chemistry and previous work in the field. The challenge of RhIII catalysed C(sp3)-H functionalisation is introduced. Chapter 5 features the development of a novel Cp*RhIII catalysed dithiane-directed amidation of unactivated C(sp3)-H bonds utilising dioxazolone amidating reagents. With the optimised method, a wide range of dioxazolone reagents as well as dithiane partners are well-tolerated. Downstream derivatisation of the amidated products is also demonstrated, including the Corey-Seebach Umpolung reaction. Chapter 6 highlights use of a transient imine directing group strategy for metal catalysed C-H functionalisation, and development of this strategy for a Cp*RhIII-catalysed transient imine-directed amidation of unactivated C(sp3)-H bonds using dioxazolone reagents. Completed optimisation studies enable amidation of a sterically hindered aldehyde in good yield, delivering a synthetically useful 1,3 amidoaldehyde derivative.
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Total synthesis of (−)-himalensine A and development of novel C(sp3)-H functionalisation reactions
2018Co-Authors: Heyao ShiAbstract:This thesis describes the 22-step enantioselective total synthesis of (-)-himalensine A, and the Cp*RhIII catalysed amidation of unactivated C(sp3)-H bonds utilising dithianes or imines as directing groups. Chapter 1 introduces the calyciphylline A-type Daphniphyllum alkaloids, their biosynthetic origin and himalensine A as one family member. Current published syntheses of these alkaloids are also highlighted as well as previous work conducted on this project. Chapter 2 focuses on the route development towards the ABCD tetracyclic core. Optimisation of the key enantioselective organocatalytic IMDAF cascade enabled the synthesis of large quantities of the tricyclic core. After elaboration to a key cycloisomerisation precursor, a reductive radical cascade was developed to close the B ring. Finally, a highly diastereoselective low-pressure hydrogenation delivered the completed tetracyclic core. Chapter 3 describes the route from the tetracyclic core through the end-game to access himalensine A. A pyridine and molecular oxygen mediated elimination/C-H oxidation was developed to access an enedione intermediate with the correct oxidation level and chemical handle required to complete the final ring. The E ring was furnished via a Stetter cyclisation and final chemoselective lactam reduction delivered the natural product. Chapter 4 summarises C-H functionalisation within the context of C-N bond forming reactions. A focus is placed on rhodium, it’s ability for directed C-H amination/amidation chemistry and previous work in the field. The challenge of RhIII catalysed C(sp3)-H functionalisation is introduced. Chapter 5 features the development of a novel Cp*RhIII catalysed dithiane-directed amidation of unactivated C(sp3)-H bonds utilising dioxazolone amidating reagents. With the optimised method, a wide range of dioxazolone reagents as well as dithiane partners are well-tolerated. Downstream derivatisation of the amidated products is also demonstrated, including the Corey-Seebach Umpolung reaction. Chapter 6 highlights use of a transient imine directing group strategy for metal catalysed C-H functionalisation, and development of this strategy for a Cp*RhIII-catalysed transient imine-directed amidation of unactivated C(sp3)-H bonds using dioxazolone reagents. Completed optimisation studies enable amidation of a sterically hindered aldehyde in good yield, delivering a synthetically useful 1,3 amidoaldehyde derivative.
Damian Ploschik - One of the best experts on this subject based on the ideXlab platform.
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corey Seebach Umpolung
2014Co-Authors: Damian PloschikAbstract:In dieser Serie werden die wichtigsten Grund- und Namensreaktionen vorgestellt. Es werden sowohl allgemeine Informationen, als auch die genauen Mechanismen erlautert.