The solvolysis (MeOH) of representative benzocondensed and cyclohexanic diastereoisomeric benzylic alcohols (title compounds) has been studied. Both systems afford mixtures of products (methyl ethers) arising from inversion or retention of configuration on the benzylic reaction centre, with an increase in the retention product on addition of a salt (LiClO4). The results obtained do not appear to support the previous hypothesis of the intermediacy in these systems of fully developed benzylic carbenium ions, pseudoaxially attacked by the nucleophile. A rationalization based on the ion-dipole pair mechanism, implying the intermediacy of different benzylic carbocationic species, is alternatively proposed.
SOLVOLYSIS OF BENZYLIC ALCOHOLS - MECHANISM AND STEREOCHEMISTRY OF THE ACID METHANOLYSIS OF DIASTEREOISOMERIC TRANS-1,2,3,4,4A,10A-HEXAHYDROPHENANTHREN-9-OL AND 4-TERT-BUTYL-1-PHENYLCYCLOHEXANOL
CROTTI, PAOLO
1991-01-01
Abstract
The solvolysis (MeOH) of representative benzocondensed and cyclohexanic diastereoisomeric benzylic alcohols (title compounds) has been studied. Both systems afford mixtures of products (methyl ethers) arising from inversion or retention of configuration on the benzylic reaction centre, with an increase in the retention product on addition of a salt (LiClO4). The results obtained do not appear to support the previous hypothesis of the intermediacy in these systems of fully developed benzylic carbenium ions, pseudoaxially attacked by the nucleophile. A rationalization based on the ion-dipole pair mechanism, implying the intermediacy of different benzylic carbocationic species, is alternatively proposed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
