Light‐Induced Activation of 7‐Dehydrocholesterol

Abstract

Fig. I. ORTEP diagram of the structure of Za in the crystal.The crystal lattice"21 of 2a accomodates two sets of mutually symmetry-independent molecules (A, B). In accord with the "P('H}-NMR spectrum, the X-ray structure analysis of 2a also indicates an interaction between C11 and the lone pair of the phosphorus, which favors the thermal decomposition (CI 1-P distance = 327 pm). The PCl bond, of ca. 188 pm, is longer than the PCillkyl bonds; this is important, since cleavage of this bond is an important prerequisite for the formation of 3a.[Z 74 1Ej German version: Angew. Chem. 94 (1982) 395The complete manuscript of this communication appears in:Angew. Chem. Suppl.