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Regioselectivity Change in the Organocatalytic Enantioselective (3+2) Cycloaddition with Nitrones through Cooperative Hydrogen‐Bonding Catalysis/Iminium Activation
Author(s) -
Prieto Liher,
JusteNavarro Veronica,
Uria Uxue,
Delso Ignacio,
Reyes Efraim,
Tejero Tomas,
Carrillo Luisa,
Merino Pedro,
Vicario Jose L.
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201605350
Subject(s) - iminium , stereocenter , cycloaddition , enantioselective synthesis , regioselectivity , nitrone , chemistry , organocatalysis , catalysis , hydrogen bond , substrate (aquarium) , dioxirane , combinatorial chemistry , organic chemistry , molecule , oceanography , geology
The reaction of nitrones with enals through iminium activation can be modulated by using cooperative hydrogen‐bonding catalysis to induce the participation of a nitrone ylide (C‐N‐C) instead of the classical C‐N‐O dipole. As a consequence, N ‐hydroxypyrrolidines are obtained, rather than the expected isoxazolidines. The reaction proceeds smoothly and high enantioselectivities are observed in all cases. By using the appropriate substrate, polysubstituted pyrrolidines incorporating quaternary stereocenters can be efficiently prepared.