The synthesis, enantiomer analysis, and configurational assignment of
dinaphth[2,1-c:1',2'-e]oxepin-3-(5H)-one, a seven-membered lactone-bri
dged chiral binaphthalene, is reported. The elucidation of the absolut
e configuration has been performed, independently by multiple scatteri
ng X-ray experiments and by circular dichroism (CD).