Alpha-vinylation of haloquinones with activated olefins under Baylis-Hillman reaction conditions


Kee-Jung Lee,, Hyoung Seok Song,, Young Seok Song,, and Chang Hoon Lee, Department of Chemical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-ku, Seoul, 133-791, South Korea
A new synthesis of mono- and di-alpha-vinylquinones based on stepwise or one-pot substitution of the halogens in 2,3-dihalo-1,4-naphthoquinones, 6,7-dihalo-5,8-quinolinediones and several corresponding monohaloquinones by DABCO-assisted enolate ion is described. Di-alpha-vinyl-1,4-quinones undergo 6 pi electrocyclization by thermally to yield 1,4-disubstituted anthraquinones readily.