REACTIVITY OF THE 1-HYDROPYRENYL ANION TOWARDS ALPHA,OMEGA-DIBROMOALKANES

The reactivity of the 1-hydropyrenyl mono-anion (1(-)) towards 1,2-dib romoethane, 1,3-dibromopropane and 1,4-dibromobutane has been examined . Six novel products were isolated from these reactions and characteri sed: spiro [cyclopropane-1,5'-(1',5'-dihydropyrene)] (2), 1,3a-dihydro -1;,3a-ethanopyrene (3), 9,10,11,11a-tetrahydro-8bH-cyclopenta[e]pyren e (4), 2,3,3a,12a-tetrahydro-1 H-cyclopenta[c]pyrene (5), 3a-(3-bromop ropyl)-3,3a-dihydropyrene (6) and, 8b,9,10,11,12,12a-hexahydrobenzo[e] pyrene (7). The formation of these products could-be rationalised by i nitial attack of the dibromoalkane at positions 3a and 5 of 1(-). Depr otonation of the initial omega-bromoalkyldihydropyrenes leads to intra molecular alkylation; the course of which depends on the length of the alkyl chain. Attempts to aromatize the products resulted, except in t he case of 5, in the fully aromatic pyrene derivatives cyclopental[cd] pyrene, benzo[e]pyrene, pyrene and the new cyclopenta-fused pyrene der ivative, 10,11 -dihydro-9H-cyclopenta[e]pyrene (9).