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organic compounds
The 1,3-diphenyl-2-azaallyl anion adds almost quantitatively to 2-phenylpropene with retention of the conformation of the anion. Two racemic diastereoisomeric [3 + 2] cycloadducts, i.e. the corresponding pyrrolidines, are formed, in which both phenyl substituents derived from the anion are cis oriented. The structures of racemic 3-methyl-r-2,c-3,c-5-triphenylpyrrolidine, C23H23N, (I), and 3-methyl-r-2,t-3,c-5-triphenylpyrrolidine, C23H23N, (II), were determined by X-ray analysis. In each crystal there is no intermolecular hydrogen bonding in either crystal.