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Enantioselective Ring Opening of meso ‐Epoxides with Silicon Tetrachloride Catalyzed by Pyridine N ‐Oxides Fused with the Bicyclo[3.3.1]nonane Framework
Author(s) -
Neniškis Algirdas,
Stončius Sigitas
Publication year - 2015
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.201500762
Subject(s) - chemistry , enantioselective synthesis , desymmetrization , epoxide , alicyclic compound , pyridine , bicyclic molecule , norbornene , catalysis , nonane , asymmetric induction , medicinal chemistry , organic chemistry , stereochemistry , copolymer , polymer
Abstract The synthesis of new chiral Lewis basic organocatalysts that contain pyridine N ‐oxide moieties fused with the bicyclo[3.3.1]nonane framework is reported. The obtained pyridine N ‐oxides were employed as catalysts in the enantioselective ring opening of meso ‐epoxides with silicon tetrachloride. Derivative 1b endowed with two 2,4‐diaryl‐substituted pyridine N ‐oxide moieties proved to be a particularly effective catalyst for desymmetrization of norbornene oxide 16i to furnish Wagner–Meerwein rearrangement product 20i in unprecedented 96 % ee . Difunctional congener 3 , which is striped of the 4‐aryl substituents, exhibited moderate to high levels of asymmetric induction (47–88 % ee ) with alicyclic epoxide substrates.