Generation and reactions of two new functionalized tricyclo[3.3.0.0 3,7]oct-1(5)-ene derivatives

The generation of the new functionalized and highly pyramidalized alkenes, 3,7-(2,2'-biphenylene)tricyclo[3.3.0.0(3,7)]oct-1(5)-ene (20) and 3,7-sulfonyldioxytricyclo[3.3.0.0(3,7)]oct-1(5)-ene (39), and their trapping with 1,3-diphenylisobenzofuran and 11,12-dimethylene-9,10-dihydro-9,10-ethanoanthracene are described. While both alkenes 20 and 39 failed to give the expected cyclobutane or diene dimers, 20 was reacted with 3,7-dimethyltricyclo[3.3.0.0(3,7)]oct-1(5)-ene (1b) to give the cross-coupled product 4,5-(2,2')-biphenylene-10,11-dimethylpentacyclo[8.2.1.1(2,5).1(4,7).1(8,11)]hexadeca-1,7-diene (33). DFT calculations [B3LYP/6-31G(d)] on compound 20 gave important parameters of this pyramidalized alkene, such as the pyramidalization angle (61.7 degrees), the strain energy (72.9 kcal/mol), and the HOMO/LUMO gap (3.79 eV).