Synthesis and Reactivity of Benzylic Epoxides Derived from 1,2,3,9,10,10a-Hexahydrophenanthrene. Search for a Unified Mechanism for the Ring Opening of 2-Aryloxiranes

Article abstract of DOI:10.1021/jo00277a034

The diastereoisomeric benzylic epoxides 4a and 4b were synthesized, and their ring-opening reactions under acidic conditions were compared with those of the known epoxides 2 and 3.The chemical behavior of 4 more nearly resembles that of 3, thus suggesting that the differences in chemical behavior between 2 and 3 could be ascribed to the different conformational rigidity of the aryl in these systems.The ring opening of 4 forms significant amounts of unsaturated alcohol and ketone in addition to the diastereoisomeric diols.The results obtained in the present study are difficult to explain by means of either of the two mechanistic schemes suggested for 2-aryloxiranes.