The first enantioselective synthesis of trans- and cis-dihydroflavonols
作者:Hendrik van Rensburg、Pieter S. van Heerden、Barend C. B. Bezuidenhoudt、Daneel Ferreira
DOI:10.1039/cc9960002747
日期:——
Epoxidation of a series of polyoxygenated chalcones with H2O2 in the presence of poly(α-amino acid) catalysts, followed by Lewis acid-catalysed phenylmethanethiol ring-opening and cyclization, afforded trans- and cis-dihydroflavonols in moderate to high enantiomeric excess and yield.
Stereoselective synthesis of flavonoids. Part 4. Trans- and cis-dihydroflavonols
作者:Hendrik van Rensburg、Pieter S. van Heerden、Barend C.B. Bezuidenhoudt、Daneel Ferreira
DOI:10.1016/s0040-4020(97)00916-2
日期:1997.10
Epoxidation of a series of poly-oxygenated chalcones with H2O2 in the presence of poly-α-aminoacids yielded chiral aromatic oxygenated oxiranes in moderate to high optical yields. Lewis acid-catalysed phenylmethanethiol ringopening of the epoxide functionality and subsequent formation of the pyranone heterocycle, afforded trans- and cis-dihydroflavonols in moderate to high enantiomeric excess and yield
在聚-α-氨基酸的存在下,用H 2 O 2对一系列多加氧的查耳酮进行环氧化,以中等至高的光学收率得到了手性芳族加氧的环氧乙烷。路易斯酸催化的苯基甲的环氧化物官能团和吡喃酮杂环的随后形成,得到ringopening反式-和CIS在中度至高度对映体过量和产量-dihydroflavonols。
Brown, Ben R.; Stuart, Ian A.; Tyrrell, A. William R., Journal of the Chemical Society. Perkin transactions I, 1984, # 11, p. 2563 - 2572
作者:Brown, Ben R.、Stuart, Ian A.、Tyrrell, A. William R.
DOI:——
日期:——
Takahashi, Hiroshi; Kubota, Yumiko; Fang, Lin, Chemical and pharmaceutical bulletin, 1986, vol. 34, # 11, p. 4597 - 4604
Synthesis and Cyclization of 1-(2-Hydroxyphenyl)-2-propen-1-one Epoxides: 3-Hydroxychromanones and -flavanones <i>versus</i> 2-(1-Hydroxyalkyl)-3-coumaranones
作者:Tamás Patonay、Albert Lévai、Csaba Nemes、Tibor Timár、Gábor Tóth、Waldemar Adam
DOI:10.1021/jo960163z
日期:1996.1.1
Competitive alpha and beta cyclization of 2'-hydroxychalcone epoxides affords 2-(alpha-hydroxybenzyl)-3-coumaranone and/or 3-hydroxyflavanones, which depends on the conditions employed. Epoxidation of 2'-hydroxychalcones by dimethyldioxirane followed by either base- or acid-catalyzed ring closure provides a novel, general, and efficient method for the synthesis of trans-3-hydroxyflavanones, which includes also the naturally occurring derivatives. Extension of this two-step procedure to 1-(2-hydroxyphenyl)-2-alken-1-ones was also accomplished. A strong preference for alpha cyclization was observed in the case of beta-unsubstituted or -monoalkylated alpha,beta-enones, while both 2,2-dimethyl-3-hydroxychromanones and 2-(1-hydroxy-1-methylethyl)-3-coumaranones were obtained from the beta,beta-dimethylated substrates.