108335-31-5Relevant articles and documents
Total Syntheses of Biologically Active Pterocarpan, Isoflavan, and Isoflavanone from Dalbergia oliveri
Singh, Dileep Kumar,Kim, Jinwoo,Sung, Jong-Hyuk,Kim, Ikyon
, p. 239 - 243 (2018)
Biological screening of the natural products from Dalbergia oliveri identified that (6aR,11aR)-3,8-dihydroxy-9-methoxypterocarpan and (3R)-7,2′-dihydroxy-4′,5′-dimethoxyisoflavanone significantly increased the proliferation of dermal papilla cells and subcutaneous injection of these compounds induced the anagen of hair cycle in animal models. These interesting biological activities led us to design a practical synthetic route to these natural products for further pharmacological evaluation. Here we report the first total syntheses of naturally occurring pterocarpan ((6aR,11aR)-3,8-dihydroxy-9-methoxypterocarpan), isoflavan ((3R)-5′-methoxyvestitol), and isoflavanone ((3R)-7,2′-dihydroxy-4′,5′-dimethoxyisoflavanone) in a racemic form. A mild ZnCl2-mediated [3 + 2] annulation method was utilized with chromenes and 2-methoxy-1,4-benzoquinone to construct a pterocarpan framework in a one-pot manner. O-methylation and reductive cleavage of the benzylic C─O bond afforded 5′-methoxyvestitol, which was transformed to isoflavanone, 7,2′-dihydroxy-4′,5′-dimethoxyisoflavanone, via a three-step sequence including DDQ-mediated benzylic oxidation.
Asymmetric reactions of 2-methoxy-1,4-benzoquinones with styrenyl systems: Enantioselective syntheses of 8-aryl-3-methoxybicyclo[4.2.0]oct-3- en-2,5-diones, 7-Aryl-3-hydroxybicyclo[3.2.1]oct-3-en-2,8-diones, 2-Aryl-6- methoxy-2,3-dihydrobenzofuran-5-ols, and pterocarpans
Engler,Letavic,Iyengar,LaTessa,Reddy
, p. 2391 - 2405 (2007/10/03)
Reactions of 2-methoxy-1,4-benzoquinones 2 and 3 with (E)- propenylbenzenes 1 promoted at -78 °C by Ti(IV)-TADDOLates prepared from diol-(+)-4 afford (1R,6R,7R,8R)-8-aryl-3-methoxy-7-methylbicyclo[4.2.0]oct- 3-en-2,5-diones 5/8 or (1R,5R,6R,7R)-7-aryl-3-hydroxy-6-methylbicyclo[3.2.1]- oct-3-en-2,8-diones 7/10 in good yield and high ee. (2S,3S)-2-Aryl-6-methoxy- 3-methyl-2,3-dihydrobenzofuran-5-ols 6/9 are also found, but in slightly lower ee. Cyclobutanes 5/8 cleanly and efficiently rearrange to the dihydrobenzofurans 6/9 without loss of enantiomeric purity upon treatment with the Ti-TADDOLates at higher temperatures. Reactions of (Z)- propenylbenzene 17 and of indene with 2 and 3 give products in moderate enantiomeric purity. Products obtained from reactions of 1-anisylcycloalkenes with 2 differ significantly in yield and enantiomeric purity. In the latter reactions, the ee's of the cyclobutane products are consistently much higher than those of the dihydrobenzofuran products. More significantly, products of different absolute configuration result from different cycloalkenes. With 1- anisylcyclopentene or 1-anisylcyclohexene, all of the products are of similar configuration and are obtained in comparable yields and ee's. However, 1- anisylcycloheptene affords products that are diastereomeric with those of the 1-anisylcyclopentene, and in lower ee's. A mechanistic model is proposed. Application of these reactions to the enantioselective synthesis of the pterocarpan class of isoflavonoid natural products is also reported.
A new regioselective synthesis of pterocarpans
Engler, Thomas A.,Combrink, Keith D.,Reddy, Jayachandra P.
, p. 454 - 455 (2007/10/02)
Pterocarpans are formed directly and efficiently via titanium(IV) catalysed reactions of 2H-chromenes and 2-alkoxy-1,4-benzoquinones.
