N-[(3aR*,3bS*)-1,3b,7,7-Tetramethyl-3a,3b,4,5,6,7,7a,7b-octahydro-3H-cyclopenta[3,4]cyclobuta[1,2]benzen-3a-yl]acetamide

The title compound, C17H27NO, is built up from a four-membered ring to which a six- and a five-membered ring are fused. The cyclohexane ring has a chair conformation, while the cyclopentene ring has an envelope conformation, with the C atom substituted by the acetamide group as the flap. The dihedral angles between the mean plane of the central cyclobutane ring and the mean planes of the cyclopentene and cyclohexane rings are 62.52 (2) and 61.06 (11)°, respectively. In the crystal, molecules are linked by N—H...O hydrogen bonds, forming chains propagating along theb-axis direction.

Facile synthesis of photoactive diaryl(hetaryl)cyclopentenes by ionic hydrogenation

A facile synthetic approach to photoactive diarylethenes comprising a cyclopentene ring as an ethene bridge was developed based on reduction of 2,3-diaryl(hetaryl)cyclopent-2-en-1-ones through an ionic hydrogenation reaction.

Pseudoaglycone of Spinosyn A

The title compound [systematic name: 9-ethyl-13-hydroxy-14-methyl-2-(3,4,5-trimethoxy-6-methyltetrahydro-2H-pyran-2-yloxy)-3,3a,5b,6,9,10,11,12,13,14,16a,16b-dodecahydro-1H-as-indaceno[3,2-d][1]oxacyclododecine-7,15(2H,5aH)-dione], C33H50O9, was obtained by hydrolysis of Spinosyn A. The fused cyclopentene ring adopts a twisted conformation, while the fused cyclohexene and cyclopentane rings are in envelope conformations with the same C atom at the flaps. In the crystal, molecules are linked by O—H...O and C—H...O hydrogen bonds into a layer parallel to theabplane.

2,4-Dibromo-2,3-dihydro-1H-inden-1-yl acetate

In the title compound, C11H10Br2O2, the cyclopentene ring fused to the benzene ring adopts an envelope conformation, with the C atom attached to the Br atom as the flap. The crystal structure does not exhibit any classical hydrogen bonds. The molecular packing is stabilized by van der Waals forces and π–π stacking interactions with a centroid–centroid distance of 3.811 (4) Å.