Synthesis 2004(12): 1941-1946  
DOI: 10.1055/s-2004-829147
PAPER
© Georg Thieme Verlag Stuttgart · New York

DABCO-Assisted Coupling of Some Activated Olefins and 2,3-Dihalo-1,4-naphthoquinones and Conversion to the Anthraquinone Derivatives

Chang Hoon Lee, Kee-Jung Lee*
Organic Synthesis Laboratory, School of Chemical Engineering, Hanyang University, Seoul 133-791, South Korea
Fax: +82(2)22984101; e-Mail: leekj@hanyang.ac.kr;
Further Information

Publication History

Received 5 March 2004
Publication Date:
13 July 2004 (online)

Abstract

A new synthesis of mono- and di-α-vinylnaphthoquinones based on stepwise or one-pot substitution of the halogens in 2,3-dihalo-1,4-naphthoquinones by DABCO-assisted enolate ion is described. Di-α-vinylnaphthoquinones undergo thermal 6π electrocyclization to yield 1,4-disubstituted anthraquinones readily.

9

When employing 0.1 equivalent of DABCO, 2a was obtained in a 9% yield. No reaction or very low yields (5%) of 2a were produced using other tertiary amines (1.2 equiv) such as DMAP, DBU and DBN.

11

Unreacted 1b (13%) was recovered.

12

No reaction occurred in the case of acrolein.