- SYNTHESIS OF SMALL MOLECULES INSPIRED BY PHOMOXANTHONE A
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Methods, compositions, and kits are provided for synthesizing bioactive chromane, the method including: constructing a tertiary ether stereocenter enantioselectively by catalyzed alkynylation of a substituted chromenone to obtain a chromanone; reducing alkyne and ketone in the chromanone to obtain a chroman; and converting ester to methyl group thereby obtaining chromane.
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Page/Page column 90
(2022/02/28)
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- Copper Bis(oxazoline)-Catalyzed Enantioselective Alkynylation of Benzopyrylium Ions
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The stereocontrolled construction of biologically relevant chromanones and tetrahydroxanthones has been achieved through the addition of alkynes to benzopyrylium trilfates under the influence of copper bis(oxazoline) catalysis. Excellent levels of enantiocontrol (63–98 % ee) are achieved in the addition of a variety of alkynes to an array of chromenones with a hydrogen in the 2-position. Promising levels of enantiocontrol (54–67 % ee) are achieved in the alkynylation of chromenones with esters in the 2-position, generating tertiary ether stereocenters resembling those frequently found in naturally occurring metabolites.
- Guan, Yong,Attard, Jonathan W.,Mattson, Anita E.
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supporting information
p. 1742 - 1747
(2020/02/05)
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- Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
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The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
- Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
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p. 17662 - 17668
(2015/02/02)
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- Highly enantioselective synthesis of isoquinuclidine by diels-alder reaction of 1,2-dihydropyridine utilizing chiral bisoxazoline-Cu(II) complex
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The enantioselective Diels-Alder (D-A) reaction between N-phenoxycarbonyl- or N-benzyloxycarbonyl-1,2-dihydropyridine (1a or 1b) and N(2)-acryloyl-N(1)-(1- naphthylmethyl)-5,5-dimethylpyrazolidin-3-one (2b) using (S,S)-bisoxazoline- Cu(II) catalyst (A, B, C or D) has been investigated. Utilizing (S,S)-t-Bu-bisoxazoline-Cu(II) catalyst C, the D-A reaction of 1a and 2 afforded the endo-(7S)-isoquinuclidines (3, 4 or 5) in good chemical yields with high enantioselectivity (up to 99% e.e.).
- Hutabarat, N.D.M. Romauli,Seki, Chigusa,Shimizu, Takashi,Hirama, Masafumi,Kohari, Yoshihito,Nakano, Hiroto,Uwai, Koji,Takano, Nobuhiro,Kwon, Eunsang,Matsuyama, Haruo
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p. 203 - 217
(2013/08/23)
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- Synthesis of non-symmetric bisoxazoline compounds. An easy way to reach tailored chiral ligands
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Bisoxazoline compounds have been used as chiral catalyst ligands in a wide variety of reactions. A great deal of effort has been aimed at the synthesis of C2-symmetric bisoxazolines but very few references exist for non-symmetric ones. As part of our studies into the possible usefulness of non-symmetric bisoxazolines, we report an easy method for the synthesis of bisoxazoline compounds bearing different substituents in each oxazoline ring.
- Garcia, Jose I.,Mayoral, Jose A.,Pires, Elisabet,Villalba, Isabel
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p. 2270 - 2275
(2007/10/03)
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- An efficient and general one-pot method for the synthesis of chiral bis(oxazoline) and pyridine bis(oxazoline) ligands
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An expeditious method for the synthesis of chiral box and pybox ligands is reported. The approach is based on a one-pot condensation reaction of chiral β-amino alcohols with a dinitrile using stoichiometric or catalytic amounts of zinc triflate. Yields gr
- Cornejo,Fraile,García,Gil,Martínez-Merino,Mayoral,Pires,Villalba
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p. 2321 - 2324
(2007/10/03)
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