- Enantioselective Halo-oxy- and Halo-azacyclizations Induced by Chiral Amidophosphate Catalysts and Halo-Lewis Acids
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Catalytic enantioselective halocyclization of 2-alkenylphenols and enamides have been achieved through the use of chiral amidophosphate catalysts and halo-Lewis acids. Density functional theory calculations suggested that the Lewis basicity of the catalyst played an important role in the reactivity and enantioselectivity. The resulting chiral halogenated chromans can be transformed to α-Tocopherol, α-Tocotrienol, Daedalin A and Englitazone in short steps. Furthermore, a halogenated product with an unsaturated side chain may provide polycyclic adducts under radical cyclization conditions.
- Lu, Yanhui,Nakatsuji, Hidefumi,Okumura, Yukimasa,Yao, Lu,Ishihara, Kazuaki
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supporting information
p. 6039 - 6043
(2018/05/14)
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- Synthesis of 1,1-dimethyl-4-indanol derivatives
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The synthesis of 1,1-dimethyl-4-indanols (3a,b) has been achieved by intramolecular Friedel-Crafts cyclization of 2-(3-methyl-2-butenyl)phenols (5a,b) or 1-methoxy-2-(3-methyl-2-butenyl)benzenes (6a,b) followed by demethylation, respectively. It was found that the solvent was critical for the formation of different products in the intramolecular Friedel-Crafts reactions of 6. The unexpected product 4-methoxy-1,1,6,6-tetramethyl-as-hydrindacene (11) was obtained from the Friedel-Crafts reactions of 6a and its structure was confirmed by X-ray diffraction analysis. The key intermediates 5a,b were prepared by ortho-alkenylation of phenols with 1-bromo-3-methyl-2-butene, and the reaction temperature exerted an obvious impact on the yield of 2-(3-methyl-2-butenyl)phenol (5a). Copyright Taylor & Francis Group, LLC.
- Wang, Yang,Wu, Jiang,Xia, Peng
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p. 2685 - 2698
(2007/10/03)
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- Regioselectivity in the ene reaction of singlet oxygen with ortho-prenylphenol derivatives
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The ene reaction of singlet oxygen with prenylated dihydroxyacetophenones led to the 2-hydroperoxy-3-methylbut-3-enyl derivatives as the major product. This original regioselectivity outlined a new effect, in competition with the previously established la
- Helesbeux, Jean-Jacques,Duval, Olivier,Guilet, David,Séraphin, Denis,Rondeau, David,Richomme, Pascal
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p. 5091 - 5104
(2007/10/03)
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- Reaction between phenols and isoprene under zeolite catalysis. Highly selective synthesis of chromans and o-isopentenylphenols
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Chromans 3 and o-isopentenylphenols 4 are synthesized in satisfactory to good yields and selectivities by the reaction of phenols and isoprene in the presence of the commercially available acid faujasite zeolite HSZ-360.
- Bigi, Franca,Carloni, Silvia,Maggi, Raimondo,Muchetti, Chiara,Rastelli, Massimo,Sartori, Giovanni
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p. 301 - 304
(2007/10/03)
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