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Divergent, Enantioselective Synthesis of Pyrroles, 3 H ‐Pyrroles and Bicyclic Imidazolines by Ag‐ or P‐Catalyzed [3+2] Cycloaddition of Allenoates with Activated Isocyanides
Author(s) -
Kok Germaine Pui Yann,
Shao PanLin,
Liao JiaYu,
Ismail Siti Nur Fairuz Bte Sheikh,
Yao Weijun,
Lu Yixin,
Zhao Yu
Publication year - 2018
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.201801768
Subject(s) - stereocenter , stereoselectivity , bicyclic molecule , enantioselective synthesis , cycloaddition , chemistry , catalysis , phosphine , aromatization , combinatorial chemistry , organocatalysis , organic chemistry , stereochemistry
The divergent, stereoselective formal [3+2] cycloadditions of allenoates with activated isocyanides catalyzed by silver or phosphine‐based catalysts were investigated. Silver catalysis is capable of delivering a range of 3 H ‐pyrroles in high stereoselectivities. These enantioenriched heterocycles can either undergo sequential cyclisation with isocyanoacetates to deliver unprecedented bicyclic imidazolines with excellent yields and stereoselectivity or undergo unusual aromatization pathways leading to polysubstituted pyrroles. On the other hand, a simple mix‐and‐go procedure using an amino acid‐derived phosphine as the catalyst produces pyrroles bearing a benzylic stereocenter with good enantioselectivity.