Synthesis,molecular, and crystalline structure of 3-benzoyl-1,2-di(ethylsulfonyl)indolizine

Reaction of pyridiniumbenzoyl methylide with (E)-1,2-di(ethylsulfonyl)-1,2-dichloroethene (which has four nucleophilic groups) occurs via a 1,3-dipolar stereo- and regio directed cycloaddition to give 3-benzoyl-1,2-di(ethylsulfonyl)indolizine the structure of which was established using x-ray crystallography. The rotation of the phenyl substituted by 72.6° relative to the indolizine ring plane and the geometry of the ethylsulfonyl groups can be explained by steric hindrance due to shortened intramolecular non-valence contacts.Deceased.A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, Moscow 117813. N. D. Zelinski Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 950–954, July, 1996. Original article submitted May 5, 1996.