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Jean-marc Campagne - One of the best experts on this subject based on the ideXlab platform.
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Stereospecific Hydrogenolysis of Lactones: Application to the Total Syntheses of (R)-ar-Himachalene and (R)-Curcumene
The Journal of organic chemistry, 2017Co-Authors: Kim Spielmann, Renata Marcia De Figueiredo, Jean-marc CampagneAbstract:A straightforward strategy for the syntheses of curcumene and ar-himachalene is reported. Synthetic highlights include a catalytic and asymmetric vinylogous Mukaiyama Reaction and a stereospecific hydrogenolysis of a tertiary benzylic center using Pd/C or Ni/Raney catalysts. Notably, using Ni/Raney, the stereoselectivity outcome (inversion vs retention) of the hydrogenolysis depends on the tertiary benzylic alcohol substitution.
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Stereospecific Hydrogenolysis of Lactones: Application to the Total Syntheses of (R)-ar-Himachalene and (R)‑Curcumene
Journal of Organic Chemistry, 2017Co-Authors: Kim Spielmann, Renata Marcia De Figueiredo, Jean-marc CampagneAbstract:A straightforward strategy for the syntheses of curcumene and ar-himachalene is reported. Synthetic highlights include a catalytic and asymmetric vinylogous Mukaiyama Reaction and a stereospecific hydrogenolysis of a tertiary benzylic center using Pd/C or Ni/Raney catalysts. Notably, using Ni/Raney, the stereoselectivity outcome (inversion vs retention) of the hydrogenolysis depends on the tertiary benzylic alcohol substitution.
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Stereospecific Hydrogenolysis of Lactones: Application to the Total Syntheses of (R)-ar-Himachalene and (R)‑Curcumene
2017Co-Authors: Kim Spielmann, Renata Marcia De Figueiredo, Jean-marc CampagneAbstract:A straightforward strategy for the syntheses of curcumene and ar-himachalene is reported. Synthetic highlights include a catalytic and asymmetric vinylogous Mukaiyama Reaction and a stereospecific hydrogenolysis of a tertiary benzylic center using Pd/C or Ni/Raney catalysts. Notably, using Ni/Raney, the stereoselectivity outcome (inversion vs retention) of the hydrogenolysis depends on the tertiary benzylic alcohol substitution
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Stereoselective Syntheses of the C1-C5, C7-C15 and C17-C24 Fragments of (+)-Discodermolide Using a Catalytic and Asymmetric Vinylogous Mukaiyama Reaction
Synlett, 2004Co-Authors: Belen Bazan‐tejeda, Marie Georgy, Jean-marc CampagneAbstract:The stereoselective syntheses of C1-C5, C7-C15 and C17-C24 fragments of (+)-discodermolide are described from a common intermediate: an α,β-unsaturated six-membered lactone obtained in one step using a catalytic and asymmetric vinylogous Mukaiyama (CAVM) Reaction.
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A straightforward enantiospecific synthesis of N-(Z)-galantinic butyl ester
Tetrahedron Letters, 2001Co-Authors: Xavier Moreau, Jean-marc CampagneAbstract:Abstract A short and efficient access to the naturally occurring amino acid galantinic acid is reported using two highly diastereoselective Reactions, namely a vinylogous Mukaiyama Reaction and a 1,3-hydroxy directed Evans reduction.
Yvan Guindon - One of the best experts on this subject based on the ideXlab platform.
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synthesis of tertiary and quaternary stereogenic centers a diastereoselective tandem Reaction sequence combining Mukaiyama and free radical based allylation
Journal of Organic Chemistry, 2005Co-Authors: Benoit Cardinaldavid, Brigitte Guérin, Yvan GuindonAbstract:Reported herein is a strategy employing a Mukaiyama Reaction in tandem with a free radical-based allyl transfer Reaction for the elaboration of functionalized tertiary and quaternary centers. The appropriate choice of alcohol-protecting group on the starting alpha-methyl-beta-hydroxyaldehyde and the nature of the Lewis acid used in the Mukaiyama Reaction provided access to 3,4-anti and 3,4-syn aldolization products, precursors of the free-radical allylation Reaction. After migration or exchange of the Lewis acid, the allyl transfer Reaction with allyltributylstannane is then performed by taking advantage of the endocyclic effect, leading to the 2,3-anti relative stereochemistry. Importantly, (13)C NMR studies of the chelated intermediates are also reported and provide additional support for the endocyclic effect. In some cases, the remarkable reactivity of the aluminum-based Lewis acids allowed the use of allyltrimethylsilane, an interesting reagent from an ecological standpoint. The isolation of a key intermediate is also indicative of an atom transfer mechanism when the silicon-based reagent is employed.
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Synthesis of 2,3-anti-3,4-anti and 2,3-anti-3,4-syn propionate motifs: a diastereoselective tandem sequence of Mukaiyama and free-radical-based hydrogen transfer Reactions.
Organic letters, 2002Co-Authors: Yvan Guindon, Michel Prévost, And Philippe Mochirian, Brigitte GuérinAbstract:Reported herein is a strategy employing a Mukaiyama Reaction in tandem with a hydrogen transfer Reaction for the elaboration of 2,3-anti-3,4-anti and 2,3-anti-3,4-syn propionate motifs. The mode of complexation is controlled through monodentate or chelate pathways for the Mukaiyama Reaction to give access to either syn or anti aldol products, precursors of the free-radical reduction Reaction. Boron Lewis acid is used to control the free-radical Reaction through the exocyclic pathway.
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Synthesis of polypropionate motifs containing the anti–anti unit
Tetrahedron Letters, 2002Co-Authors: Philippe Mochirian, Brigitte Guérin, Michel Prévost, Benoit Cardinal-david, Yvan GuindonAbstract:Abstract Reported herein is the iteration of a strategy employing a Mukaiyama Reaction in tandem with a hydrogen transfer Reaction for the elaboration of four polypropionate motifs containing the anti – anti unit. In this process, Lewis acid acts as the key element in controlling the diastereoselectivity of each step, the outcome of which is >20:1 for all of the Reactions performed.
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synthesis of propionate motifs diastereoselective tandem Reactions involving anionic and free radical based processes
Journal of the American Chemical Society, 2001Co-Authors: Yvan Guindon, Michel Prévost, Karine Houde, Benoit Cardinaldavid, Serge R Landry, Benoit Daoust, Mohammed Bencheqroun, Brigitte GuérinAbstract:Reported herein is a strategy employing a Mukaiyama Reaction in tandem with a hydrogen transfer Reaction for the elaboration of propionate motifs. The nature of the protecting groups on the chiral beta-alkoxy aldehyde and the type of Lewis acid used are varied to modulate the stereochemical outcome of the tandem Reactions. The mode of complexation is thus controlled (monodentate or chelate) for the Mukaiyama Reaction to give access to either syn or anti aldol products, precursors of the free radical reduction Reaction. The endocyclic effect is subsequently capitalized upon to control the hydrogen transfer step so that the syn-reduced product may be achieved. Proceeding with excellent yield and diastereoselectivity, the synthetic sequence proposed gives access to syn-syn and syn-anti propionate motifs. Also considered is a complementary approach using a chelation-controlled Mukaiyama Reaction in tandem with a free radical allylation Reaction under the control of the endocyclic effect that leads to the anti-anti product.
Brigitte Guérin - One of the best experts on this subject based on the ideXlab platform.
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synthesis of tertiary and quaternary stereogenic centers a diastereoselective tandem Reaction sequence combining Mukaiyama and free radical based allylation
Journal of Organic Chemistry, 2005Co-Authors: Benoit Cardinaldavid, Brigitte Guérin, Yvan GuindonAbstract:Reported herein is a strategy employing a Mukaiyama Reaction in tandem with a free radical-based allyl transfer Reaction for the elaboration of functionalized tertiary and quaternary centers. The appropriate choice of alcohol-protecting group on the starting alpha-methyl-beta-hydroxyaldehyde and the nature of the Lewis acid used in the Mukaiyama Reaction provided access to 3,4-anti and 3,4-syn aldolization products, precursors of the free-radical allylation Reaction. After migration or exchange of the Lewis acid, the allyl transfer Reaction with allyltributylstannane is then performed by taking advantage of the endocyclic effect, leading to the 2,3-anti relative stereochemistry. Importantly, (13)C NMR studies of the chelated intermediates are also reported and provide additional support for the endocyclic effect. In some cases, the remarkable reactivity of the aluminum-based Lewis acids allowed the use of allyltrimethylsilane, an interesting reagent from an ecological standpoint. The isolation of a key intermediate is also indicative of an atom transfer mechanism when the silicon-based reagent is employed.
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Synthesis of 2,3-anti-3,4-anti and 2,3-anti-3,4-syn propionate motifs: a diastereoselective tandem sequence of Mukaiyama and free-radical-based hydrogen transfer Reactions.
Organic letters, 2002Co-Authors: Yvan Guindon, Michel Prévost, And Philippe Mochirian, Brigitte GuérinAbstract:Reported herein is a strategy employing a Mukaiyama Reaction in tandem with a hydrogen transfer Reaction for the elaboration of 2,3-anti-3,4-anti and 2,3-anti-3,4-syn propionate motifs. The mode of complexation is controlled through monodentate or chelate pathways for the Mukaiyama Reaction to give access to either syn or anti aldol products, precursors of the free-radical reduction Reaction. Boron Lewis acid is used to control the free-radical Reaction through the exocyclic pathway.
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Synthesis of polypropionate motifs containing the anti–anti unit
Tetrahedron Letters, 2002Co-Authors: Philippe Mochirian, Brigitte Guérin, Michel Prévost, Benoit Cardinal-david, Yvan GuindonAbstract:Abstract Reported herein is the iteration of a strategy employing a Mukaiyama Reaction in tandem with a hydrogen transfer Reaction for the elaboration of four polypropionate motifs containing the anti – anti unit. In this process, Lewis acid acts as the key element in controlling the diastereoselectivity of each step, the outcome of which is >20:1 for all of the Reactions performed.
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synthesis of propionate motifs diastereoselective tandem Reactions involving anionic and free radical based processes
Journal of the American Chemical Society, 2001Co-Authors: Yvan Guindon, Michel Prévost, Karine Houde, Benoit Cardinaldavid, Serge R Landry, Benoit Daoust, Mohammed Bencheqroun, Brigitte GuérinAbstract:Reported herein is a strategy employing a Mukaiyama Reaction in tandem with a hydrogen transfer Reaction for the elaboration of propionate motifs. The nature of the protecting groups on the chiral beta-alkoxy aldehyde and the type of Lewis acid used are varied to modulate the stereochemical outcome of the tandem Reactions. The mode of complexation is thus controlled (monodentate or chelate) for the Mukaiyama Reaction to give access to either syn or anti aldol products, precursors of the free radical reduction Reaction. The endocyclic effect is subsequently capitalized upon to control the hydrogen transfer step so that the syn-reduced product may be achieved. Proceeding with excellent yield and diastereoselectivity, the synthetic sequence proposed gives access to syn-syn and syn-anti propionate motifs. Also considered is a complementary approach using a chelation-controlled Mukaiyama Reaction in tandem with a free radical allylation Reaction under the control of the endocyclic effect that leads to the anti-anti product.
Aede De Groot - One of the best experts on this subject based on the ideXlab platform.
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Mukaiyama and Torgov Chemistry in the Synthesis of (D-Homo) Steroid Skeletons
ChemInform, 2006Co-Authors: Florence C.e. Sarabèr, Ben J.m. Jansen, Tanya Charnikhova, Svetlana V. Drach, Alexander V. Baranovsky, Serghei Pogrebnoi, Aede De GrootAbstract:Three new, short, and efficient procedures have been developed for syntheses of steroid and D-homo steroid skeletons by application of Mukaiyama and Torgov chemistry. An important element in the first and in the second route is a Mukaiyama-Michael Reaction with transfer of the silyl group from the starting silyl enol ether to the carbonyl group of the receiving enone. In this way a new silyl enol ether is obtained which enables either a selective Reaction with the silyl enol ether in ring D as in route 1, or a selective Reaction with the unprotected carbonyl group in ring B as in route 2. In all three approaches the C12-C13 bond is constructed using a Mukaiyama Reaction of a Torgov type carbocation precursor with a silyl enol ether as the key transformation. In route 1, Zieglers triketone, which has been used before in the synthesis of 9,11 -dehydroestrone methyl ether, has been prepared in four easy steps and in 70% overall yield, using the Reactions mentioned above. In the second route a selective Grignard Reaction of vinyl magnesium bromide with the unprotected carbonyl group of methoxy tetralone leads to a Torgov type intermediate. This can be converted easily into a carbocation, which then reacts intramolecularly with the silyl enol ether in ring D, under formation of the C12-C13 bond to complete the synthesis of cis (D-homo) steroid skeletons. In the third route, C 17 substituted C,D trans coupled (D-homo) steroid skeletons have been prepared via an intermolecular addition of a carbocation, generated with ZnBr2 from a Torgov reagent, to a silyl enol ether containing ring D precursor. The adducts have been cyclized under formation of the C8-C14 bond by treatment with acid and the double bonds in the cyclized products have been reduced to all trans steroid skeletons. A chiral five membered silyl enol ether containing ring D precursor has been synthesized from carvone, and used as starting compound in the synthesis of a chiral C 17 functionalized steroid.
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A New Approach Toward the Synthesis of C,D-cis Coupled Steroid and C,D-cis Coupled D-Homosteroid Skeletons.
ChemInform, 2003Co-Authors: Svetlana Dratch, Ben J.m. Jansen, Tanya Charnikhova, Florence C.e. Sarabèr, Aede De GrootAbstract:A short and efficient procedure has been developed for the synthesis of C,D-cis coupled steroid and D-homo steroid skeletons. A Mukaiyama Reaction with transfer of the silyl group of the starting silyl enol ether to the enol of the adduct followed by addition of vinyl magnesium bromide to the unprotected carbonyl group leads to adducts which can be cyclized with ZnBr2. The synthesis of functionalized steroid skeletons in overall yields of about 50% in four steps can be achieved in this way. (C) 2003 Elsevier Science Ltd. All rights reserved.
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enantioselective synthesis of functionalised decalones by robinson annulation of substituted cyclohexanones derived from r carvone
Tetrahedron, 2000Co-Authors: Ben J.m. Jansen, Cindy C. J. Hendrikx, Nikolai Masalov, Gerrit A. Stork, T.m. Meulemans, Fliur Macaev, Aede De GrootAbstract:Abstract The copper catalysed conjugate addition of methyl magnesium iodide to cyclohexenones and trapping of the enolate as its trimethylsilyl enol ether, followed by a trityl hexachloroantimonate (TrSbCl6) catalysed Mukaiyama-Reaction, was applied to R-(−)-carvone. This proved to be an efficient method for the preparation of C-2, C-3 functionalised chiral cyclohexanones. These compounds were converted into their α-cyano ketones, which were submitted to Robinson annulation Reactions with methyl vinyl ketone. The scope and limitations of these annulations were investigated. A series of highly functionalised chiral decalones were obtained that can be used as starting compounds in the total syntheses of enantiomerically pure clerodanes.
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Enantioselective Synthesis of Functionalised Decalones by Robinson Annulation of Substituted Cyclohexanones, Derived from R-(−)-Carvone
Tetrahedron, 2000Co-Authors: Ben J.m. Jansen, Cindy C. J. Hendrikx, Nikolai Masalov, Gerrit A. Stork, T.m. Meulemans, Fliur Macaev, Aede De GrootAbstract:Abstract The copper catalysed conjugate addition of methyl magnesium iodide to cyclohexenones and trapping of the enolate as its trimethylsilyl enol ether, followed by a trityl hexachloroantimonate (TrSbCl6) catalysed Mukaiyama-Reaction, was applied to R-(−)-carvone. This proved to be an efficient method for the preparation of C-2, C-3 functionalised chiral cyclohexanones. These compounds were converted into their α-cyano ketones, which were submitted to Robinson annulation Reactions with methyl vinyl ketone. The scope and limitations of these annulations were investigated. A series of highly functionalised chiral decalones were obtained that can be used as starting compounds in the total syntheses of enantiomerically pure clerodanes.
José Alemán - One of the best experts on this subject based on the ideXlab platform.
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Development and Application of Asymmetric Organocatalytic Mukaiyama and Vinylogous Mukaiyama-Type Reactions.
Chemistry (Weinheim an der Bergstrasse Germany), 2018Co-Authors: María Frías, Wioleta Cieślik, Alberto Fraile, Anielka Rosado-abón, Alberto F. Garrido-castro, Francisco Yuste, José AlemánAbstract:Organocatalysis is a growing area that is benefiting from advances in many fields. Its implementation has begun in areas such as supramolecular chemistry, organic chemistry and natural product synthesis. While a considerable number of important publications in the field of organocatalytic Mukaiyama-type additions have been reported, they are yet to be fully covered in a review. Therefore, we would like to highlight the applications of various kinds of organocatalysts in Mukaiyama-type Reactions, while also including the vinylogous Mukaiyama variation. Herein we describe and discuss the development and current state of the art of the organocatalytic Mukaiyama Reaction, vinylogous Mukaiyama and related Reactions.
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asymmetric synthesis of rauhut currier type products by a regioselective Mukaiyama Reaction under bifunctional catalysis
Journal of the American Chemical Society, 2017Co-Authors: María Frías, Ruben Masballeste, Saira Arias, Cuauhtemoc Alvarado, José AlemánAbstract:The reactivity and the regioselective functionalization of silyl–diene enol ethers under a bifunctional organocatalyst provokes a dramatic change in the regioselectivity, from the 1,5- to the 1,3-functionalization. This variation makes possible the 1,3-addition of silyl–dienol ethers to nitroalkenes, giving access to the synthesis of tri- and tetrasubstituted double bonds in Rauhut–Currier type products. The process takes place under smooth conditions, nonanionic conditions, and with a high enantiomeric excess. A rational mechanistic pathway is presented based on DFT and mechanistic experiments.