Back in the days (1893) when few compounds were known, new ones could end up being named after the discoverer. Thus Feist is known for the compound bearing his name; the 2,3 carboxylic acid of methylenecyclopropane (1, with Me replaced by CO2H). Compound 1 itself nowadays is used to calibrate chiroptical calculations[1], which is what brought it to my attention. But about four decades ago, and now largely forgotten, both 1 and the dicarboxylic acid were famous for the following rearrangement that gives a mixture of 2 and 3[2]. I thought I might here unpick some of the wonderfully subtle stereochemical analysis that this little molecule became subjected to.
References
- E.D. Hedegård, F. Jensen, and J. Kongsted, "Basis Set Recommendations for DFT Calculations of Gas-Phase Optical Rotation at Different Wavelengths", Journal of Chemical Theory and Computation, vol. 8, pp. 4425-4433, 2012. http://dx.doi.org/10.1021/ct300359s
- J.J. Gajewski, "Hydrocarbon thermal degenerate rearrangements. IV. Stereochemistry of the methylenecyclopropane self-interconversion. Chiral and achiral intermediates", Journal of the American Chemical Society, vol. 93, pp. 4450-4458, 1971. http://dx.doi.org/10.1021/ja00747a019