A Stable Hetero-trans-cyclopentene (pages 159–160)
Prof. Dr. Adolf Krebs, Dr. Karl-Ingo Pforr, Dipl.-Chem. Walter Raffay, Dipl.-Chem. Bernd Thölke, Prof. Dr. W. A. König, Dr. Ingo Hardt and Prof. Dr. Roland Boese
Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199701591
A strongly deformed CC double bond is present in the chiral trans-cycloheptene derivative 1. Nonetheless it is thermally quite stable and can be separated into enantiomers. Two effects are responsible for this: four methyl groups in the α-positions increase the barriers for the trans–cis isomerization and the dimerization, and the introduction of Si(CH3)2 in the place of CH2 in the trans-cycloheptene reduces the ring strain.