The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform
Eder J Lenardao - One of the best experts on this subject based on the ideXlab platform.
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synthesis of terminal ethynyl aryl selenides and sulfides based on the retro Favorskii Reaction of hydroxypropargyl precursors
Chemistry: A European Journal, 2017Co-Authors: Eric F Lopes, Bianca Thais Dalberto, Gelson Perin, Diego Alves, Thiago Barcellos, Eder J LenardaoAbstract:The retro-Favorskii Reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either Csp-S or Csp-Se bonds were selectively prepared via the retro-Favorskii Reaction from the respective carbinol precursors. It was discovered that terminal chalcogen alkynes are stable for weeks if stored as a hexanes solution.
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Synthesis of Terminal Ethynyl Aryl Selenides and Sulfides Based on the Retro‐Favorskii Reaction of Hydroxypropargyl Precursors
Chemistry: A European Journal, 2017Co-Authors: Eric F Lopes, Bianca Thais Dalberto, Gelson Perin, Diego Alves, Thiago Barcellos, Eder J LenardaoAbstract:The retro-Favorskii Reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either Csp-S or Csp-Se bonds were selectively prepared via the retro-Favorskii Reaction from the respective carbinol precursors. It was discovered that terminal chalcogen alkynes are stable for weeks if stored as a hexanes solution.
Jakob Wirz - One of the best experts on this subject based on the ideXlab platform.
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the photo Favorskii Reaction of p hydroxyphenacyl compounds is initiated by water assisted adiabatic extrusion of a triplet biradical
Journal of the American Chemical Society, 2008Co-Authors: Richard S. Givens, Dominik Heger, Bruno Hellrung, Yavor Kamdzhilov, I Peter I G Conrad, Elizabeth D Cope, Julio F Matasegreda, Richard L Schowen, Jakob WirzAbstract:The p-hydroxyphenacyl group 1 is an effective photoremovable protecting group, because it undergoes an unusual photo-Favorskii rearrangement concomitant with the fast release (<1 ns) of its substrates in aqueous solution. The Reaction mechanism of the diethyl phosphate derivative 1a was studied by picosecond pump−probe spectroscopy, nanosecond laser flash photolysis, and step−scan FTIR techniques. The primary photoproduct is a triplet biradical, 33, with a lifetime of about 0.6 ns. The release of diethyl phosphate determines the lifetime of the triplet state T1(1a), τ(T1) = 60 ps in wholly aqueous solution. Formation of a new photoproduct, p-hydroxybenzyl alcohol (6), was observed at moderate water concentrations in acetonitrile. It is formed by CO elimination from the elusive spirodione intermediate (4), followed by hydration of the resulting p-quinone methide (5). Computational studies show that CO elimination from the spirodione is a very facile process.
Eric F Lopes - One of the best experts on this subject based on the ideXlab platform.
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synthesis of terminal ethynyl aryl selenides and sulfides based on the retro Favorskii Reaction of hydroxypropargyl precursors
Chemistry: A European Journal, 2017Co-Authors: Eric F Lopes, Bianca Thais Dalberto, Gelson Perin, Diego Alves, Thiago Barcellos, Eder J LenardaoAbstract:The retro-Favorskii Reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either Csp-S or Csp-Se bonds were selectively prepared via the retro-Favorskii Reaction from the respective carbinol precursors. It was discovered that terminal chalcogen alkynes are stable for weeks if stored as a hexanes solution.
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Synthesis of Terminal Ethynyl Aryl Selenides and Sulfides Based on the Retro‐Favorskii Reaction of Hydroxypropargyl Precursors
Chemistry: A European Journal, 2017Co-Authors: Eric F Lopes, Bianca Thais Dalberto, Gelson Perin, Diego Alves, Thiago Barcellos, Eder J LenardaoAbstract:The retro-Favorskii Reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either Csp-S or Csp-Se bonds were selectively prepared via the retro-Favorskii Reaction from the respective carbinol precursors. It was discovered that terminal chalcogen alkynes are stable for weeks if stored as a hexanes solution.
Richard S. Givens - One of the best experts on this subject based on the ideXlab platform.
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4-Hydroxyphenacyl Ammonium Salts: A Photoremovable Protecting Group for Amines in Aqueous Solutions
Journal of Organic Chemistry, 2015Co-Authors: Iwona Božena Bownik, Peter Šebej, Jaromír Literák, Dominik Heger, Zdeněk Šimek, Richard S. Givens, Petr KlánAbstract:Irradiation of N-protected p-hydroxyphenacyl (pHP) ammonium caged derivatives at 313 nm releases primary and secondary amines or ammonia in nearly quantitative yields via the photo-Favorskii Reaction when conducted in acidic or neutral aqueous buffered media. The Reaction efficiencies are strongly dependent on the pH with the most efficient and highest yields obtained when the pH of the media maintains the ammonium and p-hydroxyl groups as their conjugate acids. For example, the overall quantum yields of simple secondary amines release are 0.5 at acidic pH from 3.9 to 6.6 dropping to 0.1 at neutral pH 7.0 and 0.01 at pH 8.4. Speciation studies provide an acid–base profile that helps define the scope and limitations of the Reaction. When the pKa of the ammonium group is lower than that of the phenolic hydroxyl group, as is the case for the α-amino-protected amino acids, the more acidic ammonium ion deprotonates as the media pH is changed from acidic toward neutral or basic, thus diminishing the leaving gro...
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the photo Favorskii Reaction of p hydroxyphenacyl compounds is initiated by water assisted adiabatic extrusion of a triplet biradical
Journal of the American Chemical Society, 2008Co-Authors: Richard S. Givens, Dominik Heger, Bruno Hellrung, Yavor Kamdzhilov, I Peter I G Conrad, Elizabeth D Cope, Julio F Matasegreda, Richard L Schowen, Jakob WirzAbstract:The p-hydroxyphenacyl group 1 is an effective photoremovable protecting group, because it undergoes an unusual photo-Favorskii rearrangement concomitant with the fast release (<1 ns) of its substrates in aqueous solution. The Reaction mechanism of the diethyl phosphate derivative 1a was studied by picosecond pump−probe spectroscopy, nanosecond laser flash photolysis, and step−scan FTIR techniques. The primary photoproduct is a triplet biradical, 33, with a lifetime of about 0.6 ns. The release of diethyl phosphate determines the lifetime of the triplet state T1(1a), τ(T1) = 60 ps in wholly aqueous solution. Formation of a new photoproduct, p-hydroxybenzyl alcohol (6), was observed at moderate water concentrations in acetonitrile. It is formed by CO elimination from the elusive spirodione intermediate (4), followed by hydration of the resulting p-quinone methide (5). Computational studies show that CO elimination from the spirodione is a very facile process.
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The Photo-Favorskii Reaction of p-Hydroxyphenacyl Compounds Is Initiated by Water-Assisted, Adiabatic Extrusion of a Triplet Biradical
Journal of the American Chemical Society, 2008Co-Authors: Richard S. Givens, Dominik Heger, Bruno Hellrung, Yavor Kamdzhilov, Elizabeth D Cope, Ii Peter G. Conrad, Julio F. Mata-segreda, Richard L SchowenAbstract:The p-hydroxyphenacyl group 1 is an effective photoremovable protecting group, because it undergoes an unusual photo-Favorskii rearrangement concomitant with the fast release (
Richard L Schowen - One of the best experts on this subject based on the ideXlab platform.
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the photo Favorskii Reaction of p hydroxyphenacyl compounds is initiated by water assisted adiabatic extrusion of a triplet biradical
Journal of the American Chemical Society, 2008Co-Authors: Richard S. Givens, Dominik Heger, Bruno Hellrung, Yavor Kamdzhilov, I Peter I G Conrad, Elizabeth D Cope, Julio F Matasegreda, Richard L Schowen, Jakob WirzAbstract:The p-hydroxyphenacyl group 1 is an effective photoremovable protecting group, because it undergoes an unusual photo-Favorskii rearrangement concomitant with the fast release (<1 ns) of its substrates in aqueous solution. The Reaction mechanism of the diethyl phosphate derivative 1a was studied by picosecond pump−probe spectroscopy, nanosecond laser flash photolysis, and step−scan FTIR techniques. The primary photoproduct is a triplet biradical, 33, with a lifetime of about 0.6 ns. The release of diethyl phosphate determines the lifetime of the triplet state T1(1a), τ(T1) = 60 ps in wholly aqueous solution. Formation of a new photoproduct, p-hydroxybenzyl alcohol (6), was observed at moderate water concentrations in acetonitrile. It is formed by CO elimination from the elusive spirodione intermediate (4), followed by hydration of the resulting p-quinone methide (5). Computational studies show that CO elimination from the spirodione is a very facile process.
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The Photo-Favorskii Reaction of p-Hydroxyphenacyl Compounds Is Initiated by Water-Assisted, Adiabatic Extrusion of a Triplet Biradical
Journal of the American Chemical Society, 2008Co-Authors: Richard S. Givens, Dominik Heger, Bruno Hellrung, Yavor Kamdzhilov, Elizabeth D Cope, Ii Peter G. Conrad, Julio F. Mata-segreda, Richard L SchowenAbstract:The p-hydroxyphenacyl group 1 is an effective photoremovable protecting group, because it undergoes an unusual photo-Favorskii rearrangement concomitant with the fast release (
