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[摘要]:CF3SO3H-catalyzed reaction of 5-alkyl-(R)-substituted diphenylhomobenzoquinone epoxides (R = Me, iPr, tBu) provided indenoquinones, a cyclopenta[b]chromene-2-carbaldehyde, and furan-3(2H)-ones through novel cationic domino rearrangements depending on the R substituents. The mechanisms of these reactions were described by a combination of various key steps involving (i) transannular cyclization of the endo-phenyl group, (ii) epoxide and cyclopropane ring opening, (iii) ring contraction of the original quinone frame, (iv) dehydration and intramolecular SE2/SN2-Ar cyclization, as well as (v) possible pseudopericyclic cheletropic decarbonylation. |
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