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A Facile Synthesis of 2 H ‐Chromenes and 9‐Functionalized Phenanthrenes through Reactions between α,β‐Unsaturated Compounds and Arynes
Author(s) -
Zhang Tiexin,
Huang Xian,
Luling Wu and
Publication year - 2012
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.201200042
Subject(s) - phenanthrenes , aryne , chemistry , cycloaddition , aromatization , organic chemistry , combinatorial chemistry , stereochemistry , medicinal chemistry , phenanthrene , catalysis
Abstract Facile syntheses of 2 H ‐chromenes or 9‐functionalized phenanthrenes under mild conditions in moderate to good yields have been developed. They each involve annulations of arynes with α,β‐unsaturated compounds bearing different electron‐withdrawing groups (EWGs). Depending on the natures of the different EWGs, the reactions proceed by different pathways: enals react with arynes through a tandem [2+2] cycloaddition/thermal electrocyclic ring‐opening/6e‐electrocyclization sequence to afford 2 H ‐chromenes, whereas acyl‐/ethoxycarbonyl‐/cyano‐substituted styrenes undergo Diels–Alder reactions with arynes followed by aromatization to afford 9‐functionalized phenanthrenes. The scope, limitations, regioselectivities and mechanisms have been studied and are discussed in detail.