... Intensity variation Refinement method No. of parameters R n,,,, [g ' em- 7 !J [mm-ll Rim R , 3 Treatment of H-atoms Max/min Ap [ ek '1 AcOEt/Et,O ... Page 10. 1328 HELVETICA CHIMICA ACTA - Vol. 81 (1998) Crystal-Structure Determination of 3 and (E)-7a (see Table 4 and Fig. ...