Long-Range Shielding by Cyclopropyl Groups in 10-Spirocyclopropyl-9,10-dihydroanthracenes

Article abstract of DOI:10.1002/omr.1270210107

The peri protons in a series of 10-spriocyclopropyl-9,10-dihydroanthracenes have been shown to have shifts consistent with large (0.43 - 0.55 ppm) long-range shielding effects exerted by neighboring cyclopropyl groups.The shieldings are expected to be sensitive to variations in preferred conformation and, since the range of observed shifts for the five compounds studied is relatively small, it is concluded that all exhibit similar conformational preference.