Reactions of 1-naphthols with pi-acceptor p-benzoquinones: oxidative aryl coupling vs. non-oxidative electrophilic arylation.
We investigated the reactions of various 1-naphthols (NPOHs; 1) with p-benzoquinones (Qs), such as 1,4-benzoquinone (BQ) and p-chloranil (CA), as pi-electron acceptors. With electron-rich NPOHs 1a-c, oxidative biaryl coupling and subsequent dehydrogenation reaction took place selectively to give the corresponding 2,2'-binapthyl-1,1'-quinones 3a-c in excellent yield. In the case of electron-deficient NPOHs 1e, f, two different types of reactions occurred in the presence of SnCl4 and ZrO2 under similar conditions: SnCl4 mediated oxidative dimerization and trimerization of NPOH, while ZrO2 promoted electrophilic arylation of Qs with NPOH. The resulting products 3 would be useful synthetic intermediates for naturally occurring diosindigo B, biramentaceone and violet-quinone.
Takeya
Tetsuya
T
Showa Pharmaceutical University, Machida, Tokyo, Japan. takeya@ac.shoyaku.ac.jp
Kondo
Hiromu
H
Otsuka
Tsuyoshi
T
Doi
Hirohisa
H
Okamoto
Iwao
I
Kotani
Eiichi
E
D016227:Benzoquinones / Q000737:chemistry*; D004563:Electrochemistry; D004579:Electron Transport; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009284:Naphthols / Q000737:chemistry*; D010084:Oxidation-Reduction; D011083:Polycyclic Compounds / Q000138:chemical synthesis*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D017971:Tin Compounds; D015040:Zirconium
D016227:Benzoquinones; D007202:Indicators and Reagents; D009284:Naphthols; D011083:Polycyclic Compounds; D017971:Tin Compounds; C023599:stannous chloride; D015040:Zirconium; C028541:zirconium oxide