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Novel, Chiral, and Enantiopure C 2 ‐Symmetric Thioureas Promote Asymmetric Protio‐Pictet‐Spengler Reactions by Anion‐Binding Catalysis
Author(s) -
Retini Michele,
Bartoccini Francesca,
Zappia Giovanni,
Piersanti Giovanni
Publication year - 2021
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202001501
Subject(s) - enantiopure drug , chemistry , enantioselective synthesis , catalysis , tryptamine , aldehyde , pictet–spengler reaction , stereochemistry , combinatorial chemistry , medicinal chemistry , organic chemistry , biochemistry
Although anion‐binding processes are well‐known for their crucial role in molecular recognition, they have only recently been utilized for catalysis. Herein, a new class of chiral, enantiopure C 2 ‐symmetrical thioureas that, in combination with 4‐methoxybenzoic acid, promotes the enantioselective protio‐Pictet‐Spengler reaction to provide unprotected tetrahydro‐β‐carbolines in good yields (40–93 %) and moderate‐to‐high enantioselectivities (34–95 % ee) in one step from tryptamine and aldehyde derivatives is described. The formation of a chiral catalyst‐anion complex was explored by 1 H NMR.