作者:Pawel Skowronek、David A. Lightner
DOI:10.1007/s00706-002-0562-z
日期:2003.5.1
Diethyl 3,3'-di-tert-butyl-4,4'-dimethyl-2,2'-bipyrrole-5,5'-dicarboxylate was synthesized in four steps from ethyl 3,5-dimethyl-1H-pyrrole-2-carboxylate. The CH2 hydrogens of the ethyl ester groups of the former are diastereotopic in the H-1-NMR, consistent with axial chirality of the bipyrrole and restricted rotation about the 2,2-bipyrrole bond, due to the tert-butyl groups. An X-ray structure of the crystalline target compound shows the pyrrole rings are twisted out of coplanarity by 84.5degrees.