Discovery of a Long-Range Perlin Effect in a Conformationally Constrained Oxocane.

Herein, we present the crystal structure, NMR J analysis, and conformational and natural bond order analyses of tricyclic oxocane (1), resulting in the discovery of a long-range Perlin effect at C4 and C5. The normal Perlin effect (NPE) of Δ(1)JC-H = 18.38 Hz at C5 is the largest to date for a nonanomeric methylene due to an unprecedented through-space n → σ* stabilizing interaction. The NPE at C4 where Δ(1)JC-H = 6.91 Hz is nearly double those found in cyclohexanone.