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Formal Carbene Insertion into C−O or C−N Bond: An Efficient Strategy for the Synthesis of 2‐Substituted 2 H ‐Chromene Derivatives from Chromene Acetals or Hemiaminal Ethers
Author(s) -
Zhang Dan,
Hu Wenhao
Publication year - 2018
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.201800179
Subject(s) - chemistry , hemiaminal , carbene , yield (engineering) , palladium , bond cleavage , medicinal chemistry , catalysis , brønsted–lowry acid–base theory , stereochemistry , organic chemistry , combinatorial chemistry , materials science , metallurgy
We report the palladium/Brønsted acid co‐catalyzed formal insertion of carbene into the C−O or C−N bond of 2 H ‐chromene acetals or hemiaminal ethers. This transformation was initiated by the Brønsted acid‐promoted cleavage of the C−O or C−N bond, followed by modification of the leaving alcohol or amino fragments with palladium carbenes, and reassembly of the modified fragments. A variety of C‐2 functionalized 2 H ‐chromene derivatives were obtained in moderate yield (43∼75%) with good to excellent diastereoselectivities (up to >95:5 dr) under mild conditions.