Stereochemistry of the Baeyer—Villiger-Type Conversion of 4-(4-Hydroxyphenyl)butan-2-one (Raspberry Ketone) into Tyrosol Mediated by Beauveria bassiana

摘要

Feeding experiments in Beauveria bassiana (ATCC 7159) of (2R,3S)-[2,3-~2H_2]-4-(4-hydroxyphenyl)-butan-2-ol (15) and (2R,3R)-[1,3-~2H_4]-4-(4-hydroxyphenyl)-butan-2-ol (16) afford (1S)- and (1R)-[1-~2H]tyrosol (17) and (18), respectively, as indicated by NMR studies on the (+)-MTPA esters 21 and 23 and comparison with an authentic sample of the (S) enantiomer. These results indicate that the C-2, Baeyer-Villiger-type, chain shortening of the C-6-C-4 framework of the intermediate raspberry ketone 1 to give the C-6—C-2 tyrosol (4) occurs with retention of configuration. The asymmetrically labeled substrates 15 and 16 have been obtained by enzymic resolution of derivatives of (2SR,3RS)-6 and (2SR,3SR)-12, prepared, in turn, by syn catalytic reduction with deuterium and with hydrogen gas, respectively, of the (Z) enol acetates 5 and 11.