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Complete 2,5‐Diastereocontrol in the Organocatalytic Enantioselective [3+2] Cycloaddition of Enals with Azomethine Ylides Derived from α‐Iminocyanoacetates: Asymmetric Synthesis of Pyrrolidines with Four Stereocentres
Author(s) -
Reboredo Silvia,
Vicario Jose L.,
Badía Dolores,
Carrillo Luisa,
Reyes Efraím
Publication year - 2011
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201100432
Subject(s) - enantioselective synthesis , chemistry , azomethine ylide , cycloaddition , pyrrolidine , intramolecular force , organocatalysis , catalysis , ylide , stereochemistry , combinatorial chemistry , medicinal chemistry , organic chemistry , 1,3 dipolar cycloaddition
Abstract Racemic α‐iminocyanoacetates have been used as azomethine ylide precursors in the catalytic enantioselective [3+2] cycloaddition with α,β‐unsaturated aldehydes catalyzed by ( S )‐α,α‐diphenylprolinol leading to the fully stereocontrolled formation of pyrrolidine cycloadducts with four stereocentres, one of them being a quaternary one. The reaction proceeded with excellent yields, endo ‐selectivities and enantioselectivities. Remarkably, complete 2,5‐diastereoselection has also been achieved under the optimized reaction conditions, which has been explained in terms of the participation of intramolecular H‐bonding interaction which contributes to stabilize one determined geometry for the in situ generated azomethine ylide.