STRUCTURE AND ENANTIOMERIZATION OF HELICALLY TWISTED LACTONE-BRIDGED BIARYLS - A THEORETICAL-STUDY

Structures of benzo[b]naphtho[1,2-d]pyranones, helically twisted bridged biaryl precursors in stereoselective biaryl synthesis, were calculated by semiempirical (AM1, PM3) methods and compared with those obtained by ab initio calculations (MP2/6-31G*//RHF/3-21G) for one of the compounds. The structural parameters match excellently with those previously obtained through X-ray structure analyses. For the helimerization process of the title compounds, the activation barriers were determined by locating the corresponding transition structures.