
%0 Journal Article
%A Clark-Lewis, JW 
%A Dainis, I 
%A Ramsay, GC 
%T Flavan derivatives. XIV. The absolute configurations of some 1,2-diarylpropane derivatives and of some isoflavans
%J Australian Journal of Chemistry
%D 1965/07/01
%V 18
%N 7
%P 1035-1048
%K 
%R https://doi.org/10.1071/CH9651035
%U https://www.publish.csiro.au/paper/CH9651035 
%X The conversion of (+)-catechin tetramethyl ether into (-)-2-chloro-5,7,3',4'-tetramethoxyisoflavan is shown to proceed by 1,2-migration of the 2-aryl group with inversion of configuration at the 3-position of the flavan nucleus (the migration terminus). The chloroisoflavan was converted into (+)-cis-2-acetoxy-5,7,3',4'-tetramethoxyisoflavan and reduction of this gave (+)-2-(3,4-dimethoxyphenyl)-3-(2,4,6-trimethoxyphenyl)propan-1-ol. This was converted into the corresponding (+)-propane which gave (-)-methylsuccinic acid on ozonolysis. The (+)-propane therefore possesses the (8)-configuration corresponding to the (S)-configuration of the (+)-2,3-diarylpropan-1-ol and the (3s)-configuration of the (+)-cis-2-acetoxy-isoflavan. (+)-cis-2-Ethoxy- and (+)-cis-2-methoxy-5,7,3',4'-tetramethoxyisoflavan have been converted into the related (+)-1-alkoxy-2,3-diarylpropanes. Chlorination of the phloroglucinol nucleus in (+)-catechin tetramethyl ether may occur during reaction with phosphorus pentachloride and is shown to lead to 2,6-dichloro-5,7,3',4'-tetramethoxyisoflavan. Racemic cis- and laevorotatory and racemic trans-2-acetoxy-5,7,3',4'-tetramethoxyisoflavan have been prepared. Nuclear magnetic resonance and optical rotatory dispersion data for a number of isoflavans are reported. The absolute configurations of pterocarpin, homopterocarpin, and pisatin are inferred. 
