The asymmetric unit of the title compound, C(13)H(15)NO(2), the main product of a photoreaction, contains two crystallographically independent mol-ecules. In both mol-ecules, the conformation of the seven-membered ring is twist sofa and that of the five-membered rings is envelope. In the crystal, mol-ecules are linked by weak inter-molecular C-H⋯O hydrogen bonds.

In the chiral title compound, C(18)H(28)O(3), the two six-membered rings of the perhydronaphthalenone adopt a rigid chair-chair conformation and the five-membered dioxolanyl ring adopts an envelope conformation. The crystal structure is stabilized only by weak inter-actions.

In the title dihalogenated trichodermin mol-ecule, C(17)H(24)Br(2)O(4) (systematic name: 9,10-dibromo-12,13-epoxy-trichothec-9-en-4β-yl acetate), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show the same conformation, viz. chair. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope ...

IN THE TITLE TRICHODERMIN COMPOUND (SYSTEMATIC NAME: 12,13-ep-oxy-trichothec-9-en-4β-yl 4-fluoro-benzoate), C(22)H(25)FO(4), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show the different conformations, viz. chair and half-chair. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope ...

The title compound, C16H22Br2Cl2, was synthesized from β-him-achalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule is built up from fused six- and seven-membered rings and an appended three-membered ring. The six-membered ring has a half-chair conformation, whereas the seven-...

The title compound, C16H28O, was synthesized by three steps from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus atlantica). The mol-ecule is built up from fused six- and seven-membered rings and an appended three-membered ring. The six-membered ring has twist-boat conformation, whereas the...

In order to develop an improved fundamental understanding of the microscopic effects of hole trapping by oxygen vacancy sites (VO) in amorphous a-SiO2, we have performed ab initio Hartree-Fock calculations of the structure and energy of model silicon dioxide clusters. Three different precursor clusters were employed in these calculations: (A) a 15 atom cluster without rings; (B) a 39 atom clust...

Front Cover: New bat siloxanes fly to the moon: Tricyclic laddersiloxanes with larger side rings are prepared for first time from Janus rings. The obtained novel, 12-8-12-membered ring laddersiloxane has a rigid silsesquioxane body flexible oligosiloxane “wings”. Like real bat, they can move wings freely apply into host molecules or highfunctional materials. This work is found in article number...

In the title compound, C13H22N2O2, both the six-membered ring and the seven-membered lactam ring adopt chair conformations. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds between inversion-related lactam rings into centrosymmetric dimers with an R 2 (2)(8) graph-set motif. Further N-H⋯O hydrogen bonds link the molecules into [100] chains.

We describe palladium-catalyzed carbocyclization of 1,6-enynes leading to six-membered rings by water-originated hydride addition. Mechanistic features of this anomalous carbocyclization and isolation of a chiral five-membered C-Pd intermediate as an oxidized form of trifluoroacetate are also reported.