C‐Vinylation of 1,8‐Dihydroxyanthraquinone Promoted by Triphenylphosphine

Abstract

The reaction of dialkyl acetylendicarboxylates with 1,8‐dihydroxyanthraquinone in the presence of triphenylphosphine (20 mol%) produces dialkyl (E)‐2‐(1,8‐dihydroxy‐9,10‐dioxo‐9,10‐dihydro‐2‐anthracenyl)‐2‐butenedioates in good yields. When the reaction is performed in the presence of 2.2 equivalents of the acetylenic ester, a nearly 2:1 mixture of dialkyl (E)‐2‐{1,8‐dihydroxy‐7‐[(E)‐3‐methoxy‐1‐(methoxycarbonyl)‐3‐oxo‐1‐propenyl]‐9,10‐dioxo‐9,10‐dihydro‐2‐anthracenyl}‐2‐butenedioates and dialkyl (Z)‐2‐{1,8‐dihydroxy‐7‐[(E)‐3‐methoxy‐1‐(methoxycarbonyl)‐3‐oxo‐1‐propenyl]‐9,10‐dioxo‐9,10‐dihydro‐2‐anthracenyl}‐2‐butenedioates is obtained.

Keywords:

• acetylenic ester
• C‐vinylation
• 1,8‐dihydroxyanthraquinone
• triphenylphosphine

Acknowledgments

We are grateful to the Institute for Colorants, Paint, and Coatings and Tarbiat Modares University for financial support.