
TY  - JOUR
A1  - Clark-Lewis, JW 
A1  - Dainis, I 
A1  - Ramsay, GC 
T1  - Flavan derivatives. XIV. The absolute configurations of some 1,2-diarylpropane derivatives and of some isoflavans
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1965
VL  - 18
IS  - 7
SP  - 1035
EP  - 1048
KW  - 
UR  - https://doi.org/10.1071/CH9651035 
N2  - 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. 
ER  -

