What is Baeyer strain theory?
The Baeyer strain theory, which I proposed in 1885, posits that the stability of a cyclic organic compound depends on how much its bond angles deviate from the ideal tetrahedral angle of 109.5 degrees. For example, cyclopropane, with its 60-degree angles, is highly strained and reactive, while cyclohexane, with angles near 109.5 degrees, is stable. I used mechanical analogies—like a bent spring—to describe this strain. The theory successfully predicted that five- and six-membered rings are most stable, which I confirmed through synthesis and reactivity studies. However, later work by others, such as Hermann Sachse, showed that larger rings can also be stable due to puckering, which my original model did not account for. Nonetheless, the strain concept remains fundamental in understanding ring-closure reactions and molecular architecture.
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