The fully substituted 12-membered macrocycle of the cubitane-type diterpenoids has been assembled in an enantioselective manner following a novel "bridge-and-cut" strategy. Hydroxyalkylation of (S)-carvone afforded a carvonylgeraniol, which underwent transannular cyclization on treatment with samarium diiodide in THF. Fragmentation of one of the shorter bridges of the resulting [8.2.2]bicycle liberated the 12-membered ring with the desired cis-arrangement of the isopropenyl side chains.

Isobutylammonium selenite and its sesquihydrate were obtained in low yields by reaction of selenium dioxide with the neat amine in the presence of small amounts of water. Both structures were determined by X-ray methods and proved to contain two independent formula units. In both cases, layer structures [(CH 3 ) 2 CHCH 2 NH 3 ] 2 [SeO 3 ] are formed in which all NH hydrogen atoms act as single hydrogen bond donors, and all selenite oxygen atoms accept two hydrogen bonds. The layers contain six independent rings; the anhydrous substance has all rings of graph set R 3 4 (10), whereas the sesquihydrate has two each of R 4 4 (12), R 2 4 (8) and R 3 4 (10). The three independent water molecules of the sesquihydrate attach themselves to the layer structure by further classical hydrogen bonds to the selenite oxygen atoms.