The bond length between C8-C9 in (1′R,4′S,4a′R,8a′S)-6′,7′-dimethyl-1′,4′,4a′,8a′-tetrahydrospiro [cyclopropane-1,9′-[1,4]methanonaphthalene]-5′,8′-dione is 1.571 (2) Å and between C7-C12 is 1.567 (2) Å which are longer than the corresponding bond length for saturated bicyclic systems (1.531-1.535Å). This paper reports the correlation between bond length and the ease of retro Diels−Alder reaction.

Polycyclics containing biaryls have been prepared via application of cross-enyne metathesis and the Diels−Alder reaction. Here, ethylene and 1,5-hexadiene were used as a cross-metathesis partners to generate key diene intermediates.

The synthesis of substituted cage [4.4.2]propellanes and D₃-trishomocubanes bearing spiro linkage have been assembled with the aid of Diels–Alder reaction and ring-rearrangement as key steps. Here, readily available 1,4-hydroquinone, isoprene, spiro[2.4]hepta-4,6-diene and spiro[4.4]nona-1,3-diene were usedas starting materials. The unusual rearrangement of cage propellanes with zinc/acetic acid produced D₃-trishomocubanes in good yields.

We have developed a simple synthetic strategy to spirofluorene derivatives via ring-closing metathesis and Suzuki–Miyaura cross-coupling reactions as key steps. To this end, we have used readily available starting materials to generate a library of spirofluorene derivatives under mild reaction conditions