The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Varinder K. Aggarwal - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of isothiocineole and application in multigram scale Sulfur Ylide mediated asymmetric epoxidation and aziridination
Synthesis, 2018Co-Authors: Martin P O Fearraigh, Eoghan M. Mcgarrigle, Ona Illa, Johnathan V Matlock, Varinder K. AggarwalAbstract:The synthesis of the chiral sulfide isothiocineole from limonene and elemental Sulfur on multi-gram scale and its alkylation to make >50 g of the corresponding benzylsulfonium salt are described. The application of this salt to the Sulfur Ylide-mediated asymmetric epoxidation of aldehydes and the asymmetric aziridination of imines on a >5 g scale is demonstrated.
-
synthesis of quinine and quinidine using Sulfur Ylide mediated asymmetric epoxidation as a key step
Tetrahedron-asymmetry, 2010Co-Authors: Muhammad Arshad, Eoghan M. Mcgarrigle, Alejandro M Fernandez, Varinder K. AggarwalAbstract:The epoxidation of meroquinene aldehyde with a chiral Sulfur Ylide as the key step in the synthesis of quinine and quinidine is described. The epoxidation reactions proceed under reagent control with high selectivity and good yield. The effect of sulfide and Ylide substituents on the stereochemical outcome of the reaction is discussed.
-
practical and highly selective Sulfur Ylide mediated asymmetric epoxidations and aziridinations using an inexpensive readily available chiral sulfide applications to the synthesis of quinine and quinidine
Journal of the American Chemical Society, 2010Co-Authors: Ona Illa, Eoghan M. Mcgarrigle, Muhammad Arshad, Abel Ros, Varinder K. AggarwalAbstract:Heating one of the most abundant naturally occurring inorganic chemicals (elemental Sulfur) with one of the most readily available homochiral molecules (limonene) gives a one-step synthesis of a chiral sulfide which exhibits outstanding selectivities in Sulfur Ylide mediated asymmetric epoxidations and aziridinations. In particular reactions of benzyl and allylic sulfonium salts with both aromatic and aliphatic aldehydes gave epoxides with perfect enantioselectivities and the highest diastereoselectivities reported to date. In addition reactions with imines gave aziridines again with the highest enantioselectivities and diastereoselectivities reported to date. The reactions are scaleable, and the sulfide can be reisolated in high yield. The epoxidation has been used as the key step in a convergent and stereoselective synthesis of each of the diastereoisomers of the cinchona alkaloids, quinine and quinidine.
-
homologation and alkylation of boronic esters and boranes by 1 2 metallate rearrangement of boron ate complexes
Chemical Record, 2009Co-Authors: Stephen P Thomas, Vishal Jheengut, Rosalind M French, Varinder K. AggarwalAbstract:Organoboranes and boronic esters readily undergo nucleophilic addition, and if the nucleophile also bears an α-leaving group, 1,2-metallate rearrangement of the ate complex results. Through such a process a carbon chain can be extended, usually with high stereocontrol and this is the focus of this review. A chiral boronic ester (substrate control) can be used for stereocontrolled homologations with (dichloromethyl)lithium in the presence of ZnCl2. Subsequent alkylation by an organometallic reagent also occurs with high levels of stereocontrol. Chiral lithiated carbanions (reagent control) can also be used for the reaction sequence with achiral boronic esters and boranes. Aryl-stabilized Sulfur Ylide derived chiral carbanions can be homologated with a range of boranes including vinyl boranes in good yield and high diastereo- and enantioselectivity. Lithiated alkyl chlorides react with boronic esters, again with high stereocontrol, but both sets of reactions are limited in scope. Chiral lithiated carbamates show the greatest substrate scope and react with both boronic esters and boranes with excellent enantioselectivity. Furthermore, iterative homologation with chiral lithiated carbamates allows carbon chains to be "grown" with control over relative and absolute ste- reochemistry. The factors responsible for stereocontrol are discussed. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 24-39; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20168
-
Sulfur Ylide mediated three component aziridination and epoxidation reactions using vinyl sulfonium salts
ChemInform, 2008Co-Authors: Christoforos G Kokotos, Eoghan M. Mcgarrigle, Varinder K. AggarwalAbstract:Coupling of diphenylvinyl sulfonium triflate with nucleophiles and either aldehydes or imines gives epoxides and aziridines, respectively, in a three-component reaction. cis-Aziridines could be formed in good diastereomeric ratio, and the selectivity was correlated to the reactivity of the imine. This represents the first study of cis/trans selectivity in the reactions of imines with non-stabilized Sulfur Ylides.
Jianbo Wang - One of the best experts on this subject based on the ideXlab platform.
-
catalytic 2 3 sigmatropic rearrangement of Sulfur Ylide derived from metal carbene
Coordination Chemistry Reviews, 2010Co-Authors: Yan Zhang, Jianbo WangAbstract:This paper reviews the most recent development of [2,3]-sigmatropic rearrangement of Sulfur Ylide generated from the reaction of sulfide with metal carbene. The metal carbene was formed from decomposition of diazo compounds catalyzed by transition metal complexes such as Cu(I) and Rh(II).
-
highly efficient 2 3 sigmatropic rearrangement of Sulfur Ylide derived from rh ii carbene and sulfides in water
ChemInform, 2007Co-Authors: Mingyi Liao, Jianbo WangAbstract:The Doyle–Kirmse reaction, namely the [2,3]-sigmatropic rearrangement of sulfonium Ylides generated from transition metal carbenoids and sulfides has been, for the first time, carried out in water.
-
highly stereoselective 2 3 sigmatropic rearrangement of Sulfur Ylide generated through cu i carbene and sulfides
ChemInform, 2006Co-Authors: Lingling Peng, Xiu Zhang, Jianbo WangAbstract:A highly stereoselective [2,3]-sigmatropic rearrangement of Sulfur Ylide generated through Cu(I) carbene and allyl and propargyl sulfides by a double asymmetric induction approach that combines a chiral camphor sultam auxiliary and Cu(I) catalyst with chiral or achiral diimine ligands has been developed.
Joel L Teran - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of indoloazocine derivatives from a chiral indole amide stabilized Sulfur Ylide
ChemInform, 2013Co-Authors: Maira Juarezcalderon, David M Aparicio, Dino Gnecco, Jorge R Juarez, Laura Orea, Angel Mendoza, Fernando Sartillopiscil, Esther Del Olmo, Joel L TeranAbstract:The reaction of Sulfur Ylide (I) with aldehydes is optimized to afford diastereomeric trans-epoxides (III) selectively.
-
synthesis of the indoloazocine derivatives from a chiral indol amide stabilized Sulfur Ylide
Tetrahedron Letters, 2013Co-Authors: Maira Juarezcalderon, David M Aparicio, Dino Gnecco, Jorge R Juarez, Laura Orea, Angel Mendoza, Fernando Sartillopiscil, Esther Del Olmo, Joel L TeranAbstract:Abstract We present here a synthetic route for the access to a series of diverse indoloazocine derivatives through selective epoxidation of chiral sulfonium salt 4, which reacts with diverse aromatic and aliphatic aldehydes to give trans-glycidic amides, followed by an intramolecular electrophilic aromatic substitution promoted by Cu(OTf)2 giving the desired heterocyclic compound in a high chemical yield. Using this strategy, the total synthesis of (S,R)-(+)-norbalasubramide was achieved.
-
application of amide stabilized Sulfur Ylide reactivity to the stereodivergent synthesis of r s and s r reboxetine
Tetrahedron-asymmetry, 2009Co-Authors: David M Aparicio, Dino Gnecco, Jorge R Juarez, Joel L Teran, Alberto Galindo, Maria L Orea, Angel MendozaAbstract:A simple access to (R,S)- and (S,R)-reboxetine from a single chiral sulfonium salt 4 is reported. This approach, based on a stabilized Sulfur Ylide-mediated epoxidation, followed by a regioselective opening reaction, enables the preparation of these two potentially biologically active compounds in 35.6% and 13.7% overall yield.
Eoghan M. Mcgarrigle - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of isothiocineole and application in multigram scale Sulfur Ylide mediated asymmetric epoxidation and aziridination
Synthesis, 2018Co-Authors: Martin P O Fearraigh, Eoghan M. Mcgarrigle, Ona Illa, Johnathan V Matlock, Varinder K. AggarwalAbstract:The synthesis of the chiral sulfide isothiocineole from limonene and elemental Sulfur on multi-gram scale and its alkylation to make >50 g of the corresponding benzylsulfonium salt are described. The application of this salt to the Sulfur Ylide-mediated asymmetric epoxidation of aldehydes and the asymmetric aziridination of imines on a >5 g scale is demonstrated.
-
synthesis of quinine and quinidine using Sulfur Ylide mediated asymmetric epoxidation as a key step
Tetrahedron-asymmetry, 2010Co-Authors: Muhammad Arshad, Eoghan M. Mcgarrigle, Alejandro M Fernandez, Varinder K. AggarwalAbstract:The epoxidation of meroquinene aldehyde with a chiral Sulfur Ylide as the key step in the synthesis of quinine and quinidine is described. The epoxidation reactions proceed under reagent control with high selectivity and good yield. The effect of sulfide and Ylide substituents on the stereochemical outcome of the reaction is discussed.
-
practical and highly selective Sulfur Ylide mediated asymmetric epoxidations and aziridinations using an inexpensive readily available chiral sulfide applications to the synthesis of quinine and quinidine
Journal of the American Chemical Society, 2010Co-Authors: Ona Illa, Eoghan M. Mcgarrigle, Muhammad Arshad, Abel Ros, Varinder K. AggarwalAbstract:Heating one of the most abundant naturally occurring inorganic chemicals (elemental Sulfur) with one of the most readily available homochiral molecules (limonene) gives a one-step synthesis of a chiral sulfide which exhibits outstanding selectivities in Sulfur Ylide mediated asymmetric epoxidations and aziridinations. In particular reactions of benzyl and allylic sulfonium salts with both aromatic and aliphatic aldehydes gave epoxides with perfect enantioselectivities and the highest diastereoselectivities reported to date. In addition reactions with imines gave aziridines again with the highest enantioselectivities and diastereoselectivities reported to date. The reactions are scaleable, and the sulfide can be reisolated in high yield. The epoxidation has been used as the key step in a convergent and stereoselective synthesis of each of the diastereoisomers of the cinchona alkaloids, quinine and quinidine.
-
Sulfur Ylide mediated three component aziridination and epoxidation reactions using vinyl sulfonium salts
ChemInform, 2008Co-Authors: Christoforos G Kokotos, Eoghan M. Mcgarrigle, Varinder K. AggarwalAbstract:Coupling of diphenylvinyl sulfonium triflate with nucleophiles and either aldehydes or imines gives epoxides and aziridines, respectively, in a three-component reaction. cis-Aziridines could be formed in good diastereomeric ratio, and the selectivity was correlated to the reactivity of the imine. This represents the first study of cis/trans selectivity in the reactions of imines with non-stabilized Sulfur Ylides.
-
Synthesis and application of easily recyclable thiomorpholines for use in Sulfur Ylide mediated asymmetric epoxidation of aldehydes.
Chemistry an Asian journal, 2008Co-Authors: Markus Hansch, Ona Illa, Eoghan M. Mcgarrigle, Varinder K. AggarwalAbstract:Chiral nonracemic thiomorpholines have been synthesized in four to six steps from limonene or achiral alkenes using alpha-methylbenzylamine to control absolute stereochemistry. These aminosulfides have been used to generate Sulfur Ylides, which have been applied in the asymmetric epoxidation of aldehydes as easily recoverable catalysts. Excellent yields (up to 98 %), enantioselectivities (up to 97:3 e.r.), and diastereoselectivities (>or=98:2 trans/cis) were achieved in these epoxidations and the sulfides were easily recovered in high yield (up to 97 %) by simple acid/base extraction.
Angel Mendoza - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of indoloazocine derivatives from a chiral indole amide stabilized Sulfur Ylide
ChemInform, 2013Co-Authors: Maira Juarezcalderon, David M Aparicio, Dino Gnecco, Jorge R Juarez, Laura Orea, Angel Mendoza, Fernando Sartillopiscil, Esther Del Olmo, Joel L TeranAbstract:The reaction of Sulfur Ylide (I) with aldehydes is optimized to afford diastereomeric trans-epoxides (III) selectively.
-
synthesis of the indoloazocine derivatives from a chiral indol amide stabilized Sulfur Ylide
Tetrahedron Letters, 2013Co-Authors: Maira Juarezcalderon, David M Aparicio, Dino Gnecco, Jorge R Juarez, Laura Orea, Angel Mendoza, Fernando Sartillopiscil, Esther Del Olmo, Joel L TeranAbstract:Abstract We present here a synthetic route for the access to a series of diverse indoloazocine derivatives through selective epoxidation of chiral sulfonium salt 4, which reacts with diverse aromatic and aliphatic aldehydes to give trans-glycidic amides, followed by an intramolecular electrophilic aromatic substitution promoted by Cu(OTf)2 giving the desired heterocyclic compound in a high chemical yield. Using this strategy, the total synthesis of (S,R)-(+)-norbalasubramide was achieved.
-
application of amide stabilized Sulfur Ylide reactivity to the stereodivergent synthesis of r s and s r reboxetine
Tetrahedron-asymmetry, 2009Co-Authors: David M Aparicio, Dino Gnecco, Jorge R Juarez, Joel L Teran, Alberto Galindo, Maria L Orea, Angel MendozaAbstract:A simple access to (R,S)- and (S,R)-reboxetine from a single chiral sulfonium salt 4 is reported. This approach, based on a stabilized Sulfur Ylide-mediated epoxidation, followed by a regioselective opening reaction, enables the preparation of these two potentially biologically active compounds in 35.6% and 13.7% overall yield.
