Friedel–Crafts alkylation reaction of β‐naphthols with donor–acceptor aminocyclopropane was developed. In the presence of a copper complex derived from Cu(OTf)2 and bisoxazoline, a series of γ‐substituted γ‐aminobutyric acid derivatives were obtained with good yields (up to 98 %) and excellent enantioselectivities (up to 98 %). Using this catalytic system, the 2‐amino cyclopropane‐1,1‐dicarboxylate was obtained
Reversal of Enantioselectivity Approach to BINOLs via Single and Dual 2-Naphthol Activation Modes
作者:Hun Young Kim、Shinobu Takizawa、Hiroaki Sasai、Kyungsoo Oh
DOI:10.1021/acs.orglett.7b01734
日期:2017.7.21
A mechanism-driven enantiodivergent approach to chiral 1,1′-bi-2-naphthols via catalytic asymmetric oxidative coupling of 2-naphthol derivatives is described for the first time. By utilizing 2-naphthol derivatives with low oxidation potential, the substrates were activated by either chiral mononuclear or dinuclear vanadium(V) catalyst to promote distinctively different asymmetric reaction pathways:
A metal‐free, one‐potsynthesis of 1,2‐naphthoquinone was accomplished from 2‐naphthol by utilizing economically cheap NBS under open air conditions. Initial formation of 1,1‐dibromonaphthalen‐2‐one and subsequent transformation afforded the 1,2‐naphthoquinone. This oxidation was completed within 30 min and had broad substrate scope. Moreover, this system tolerated heterocyclic systems and was also
Copper-catalyzed divergent oxidative pathways of 2-naphthol derivatives: ortho-naphthoquinones versus 2-BINOLs
作者:H. Y. Kim、S. Takizawa、K. Oh
DOI:10.1039/c6ob01183g
日期:——
aerobic oxidation of 2-naphthol derivatives to ortho-naphthoquinones whereas switching the catalyst system to Cu(OAc)2–DBN under an argon atmosphere allows the oxidative coupling of 2-naphthols to 1,1′-bi-2-naphthols (BINOLs) in good to excellent yields.
The reaction of 2-(trimethylsilyl) phenyl triflate with aroylacetones in the presence of CsF gave the corresponding 4-aryl-2-naphthols. Substituted triflates also reacted with aroylacetones to afford 4-aryl-2-naphthols regioselectively. The enantioselective oxidation of 4aryl-2-naphthols with a chiral tridentate oxovanadium(IV) complex furnished the corresponding 4,4'-biaryl-1,1'-binaphthols in good yields.