| Abstract: | The thermal rearrangement of 7 -propargyloxy-cycloheptatriene in decane solution at 180°C gave bicyclo[3.3.2]deca-3,7,9-trien-2-one ( 13 ) and the unstable 2,7-dihydro-cyclohepta[ b ]-pyran ( 12 ) (Scheme 2). The structures of these compounds were determined mainly by NMR. spectroscopy. Derivatives of 13 were also identified by comparison with known compounds (Scheme 3). Possible mechanisms for the formation of 13 and 12 are outlined in Schemes 5 and 6 respectively. The thermal rearrangement of 2-propargyloxy-cycloheptatrienone ( 21 ) gave, in high yield, 2-methyl-8H-cyclohepta[b]furan-8-one ( 22 ) (Scheme 7). |
