TRANS-ANNULAR REACTIONS OF DIBENZO[A,D]CYCLOALKENES .1. SYNTHESIS OF DIBENZO[A,D]CYCLOOCTEN-6,12-IMINES AND "DIBENZO[A,D]CYCLOHEPTEN-5,10-IMINES

A strategy for the synthesis of dibenzo[a, d]cycloocten-6, 12-imines based on the initial construction of a hydrocarbon framework containing the appropriate functionality for transannular nitrogen ring closure was developed. The key to this approach was the synthesis of the symmetrical diketone, 5, 6, 7, 12-tetrahydrodi-benzo[a, d]cyclooctene-6, 12-dione (15). Reductive animation of 15 occurred regioselectively at the 6 position giving rise directly to the dibenzocycloocten-6, 12-imine ring system by transannular carbinolamine formation. The diketone 15 was converted through the oxime 26 to the hydroxylamine 28. Thermal cyclization of 28 to 29 established a second transannular route to the dibenzo[a, d]cycloocten-6, 12-imines. This latter method also was used successfully for the synthesis of 10, ll-dihydro-5ff-dibenzo[a, d]cyclohepten-5, 10-imines. The proximity of functional groups at the 6 and 12 positions of dibenzo[a, d]cyclooctanes which favored nitrogen bridging reactions also promoted other transannular reactions such as the facile conversion of 26 to 27. © 1979, American Chemical Society. All rights reserved.