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[4+2] Cycloaddition of ortho ‐Quinone Methides Promoted by Ionic Liquids: an Efficient and Mild Protocol for the Synthesis of Tetrahydropyranobenzopyrans
Author(s) -
Yadav J. S.,
Subba Reddy B. V.,
Sadashiv K.,
Padmavani B.
Publication year - 2004
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.200303198
Subject(s) - chemistry , cycloaddition , quinone , ionic liquid , ionic bonding , combinatorial chemistry , protocol (science) , organic chemistry , medicinal chemistry , catalysis , ion , medicine , alternative medicine , pathology
The stereoselective synthesis of trans‐ annelated pyrano[3,2‐ c ]benzopyrans has been achieved by intramolecular [4+2] cycloaddition of o ‐benzoquinone methides that are generated in situ from o ‐hydroxybenzaldehydes and unsaturated alcohols using an air‐ and moisture‐stable ionic liquid, i.e., 1‐butyl‐3‐methylimidazolium tetrafluoroborate [bmim]BF 4 under mild and neutral conditions.