Neopulchellin Conformation

Neopulchellin was found to show that the cycloheptane ring fused to the butyrolactone adopts a boat conformation both in solid and in solution, in contrast with the half-chair form in the translactone isomer, pulchellin (!), on the basis of X-ray diffraction of 1 " 1 and comparison of 400 MHz H-nmr and cd spectra of 1 and 3.