The Experts below are selected from a list of 6 Experts worldwide ranked by ideXlab platform
Janick Ardisson - One of the best experts on this subject based on the ideXlab platform.
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secondary allyltitanium iv reagents in aldehyde allylation i extension of the Hoppe Reaction to γ alkoxy secondary allyl carbamates
Synthesis, 2004Co-Authors: Patrick Razon, Sylvie Dhulut, Sophie Bezzeninelafollee, Jacques Courtieu, Ange Pancrazi, Janick ArdissonAbstract:An efficient access to optically active (R)- or (S)-γ-alkoxy allyltitanium(IV) intermediates, in aldehyde allylation Reactions, is described. Enantiomeric γ-alkoxy secondary allyl carbamates (R)- and (S)-14 were first prepared. Determination of their enantiomeric excess was realised on the corresponding deuterated isotopic derivatives by NMR in chiral liquid media. Subsequent aldehyde allylation Reaction with propanal performed under Hoppe n-BuLi.(-)-sparteine/Ti(Oi-Pr) 4 or n-BuLi.TMEDA/Ti(Oi-Pr) 4 conditions, led to both enantiomeric homoallylic alcohols 15 or ent-15 in 90% yield, 100% ed and 80% ee.
Peter O'brien - One of the best experts on this subject based on the ideXlab platform.
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Development of a Catalytic Asymmetric Variant of Hoppe’s O-Alkyl Carbamate Deprotonation Methodology
Synthesis, 2006Co-Authors: Matthew J. Mcgrath, Peter O'brienAbstract:The optimisation of a ligand-exchange approach to catalytic asymmetric deprotonation of O-alkyl carbamates and subsequent electrophilic trapping (the 'Hoppe Reaction') is presented. The method uses s-BuLi and sub-stoichiometric amounts of a chiral diamine [(-)-sparteine or the (+)-sparteine surrogate] in conjunction with an achiral 'regenerating' diamine (bisisopropyl bispidine) for the deprotonation and proceeds with good yields (up to 84%) and high enantioselectivity (up to 94:6 er). The first applications of this catalytic asymmetric deprotonation methodology in natural product synthesis are also described.
Patrick Razon - One of the best experts on this subject based on the ideXlab platform.
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secondary allyltitanium iv reagents in aldehyde allylation i extension of the Hoppe Reaction to γ alkoxy secondary allyl carbamates
Synthesis, 2004Co-Authors: Patrick Razon, Sylvie Dhulut, Sophie Bezzeninelafollee, Jacques Courtieu, Ange Pancrazi, Janick ArdissonAbstract:An efficient access to optically active (R)- or (S)-γ-alkoxy allyltitanium(IV) intermediates, in aldehyde allylation Reactions, is described. Enantiomeric γ-alkoxy secondary allyl carbamates (R)- and (S)-14 were first prepared. Determination of their enantiomeric excess was realised on the corresponding deuterated isotopic derivatives by NMR in chiral liquid media. Subsequent aldehyde allylation Reaction with propanal performed under Hoppe n-BuLi.(-)-sparteine/Ti(Oi-Pr) 4 or n-BuLi.TMEDA/Ti(Oi-Pr) 4 conditions, led to both enantiomeric homoallylic alcohols 15 or ent-15 in 90% yield, 100% ed and 80% ee.
Sylvie Dhulut - One of the best experts on this subject based on the ideXlab platform.
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secondary allyltitanium iv reagents in aldehyde allylation i extension of the Hoppe Reaction to γ alkoxy secondary allyl carbamates
Synthesis, 2004Co-Authors: Patrick Razon, Sylvie Dhulut, Sophie Bezzeninelafollee, Jacques Courtieu, Ange Pancrazi, Janick ArdissonAbstract:An efficient access to optically active (R)- or (S)-γ-alkoxy allyltitanium(IV) intermediates, in aldehyde allylation Reactions, is described. Enantiomeric γ-alkoxy secondary allyl carbamates (R)- and (S)-14 were first prepared. Determination of their enantiomeric excess was realised on the corresponding deuterated isotopic derivatives by NMR in chiral liquid media. Subsequent aldehyde allylation Reaction with propanal performed under Hoppe n-BuLi.(-)-sparteine/Ti(Oi-Pr) 4 or n-BuLi.TMEDA/Ti(Oi-Pr) 4 conditions, led to both enantiomeric homoallylic alcohols 15 or ent-15 in 90% yield, 100% ed and 80% ee.
Sophie Bezzeninelafollee - One of the best experts on this subject based on the ideXlab platform.
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secondary allyltitanium iv reagents in aldehyde allylation i extension of the Hoppe Reaction to γ alkoxy secondary allyl carbamates
Synthesis, 2004Co-Authors: Patrick Razon, Sylvie Dhulut, Sophie Bezzeninelafollee, Jacques Courtieu, Ange Pancrazi, Janick ArdissonAbstract:An efficient access to optically active (R)- or (S)-γ-alkoxy allyltitanium(IV) intermediates, in aldehyde allylation Reactions, is described. Enantiomeric γ-alkoxy secondary allyl carbamates (R)- and (S)-14 were first prepared. Determination of their enantiomeric excess was realised on the corresponding deuterated isotopic derivatives by NMR in chiral liquid media. Subsequent aldehyde allylation Reaction with propanal performed under Hoppe n-BuLi.(-)-sparteine/Ti(Oi-Pr) 4 or n-BuLi.TMEDA/Ti(Oi-Pr) 4 conditions, led to both enantiomeric homoallylic alcohols 15 or ent-15 in 90% yield, 100% ed and 80% ee.