Janet Finer

Ilimaquinone, a sesquiterpenoid quinone from a marine sponge

Abstract Ilimaquinone (1) is a new sponge metabolite of composition C22H30O4. Its structure, which was determined by spectral correlations and X-ray crystallography, comprises a rearranged drimane sesquiterpene moiety linked to a 2-hydroxy-5-methoxybenzoquinone at C-3.

Diterpenes from Dictyota dichotoma

Two new and two known diterpenes were isolated from Dictyota dichotoma. The structures of the new diterpenes were elucidated from spectral and X-ra

Synthesis and structure of dicarbonyldi-η-cyclopentadienylbis(μ-thiocarbonyl)diiron, a thiocarbonyl analog of the dicarbonyl-η-cycglopentadienyliron dimer

Abstract Sodium hydride reduction of (η-C5H5)Fe(CO)2(CS)+ gives cis- and trans[(η-C5H5)Fe(CS) (CO)]2. The trans isomer slowly converts to a cis—trans mixture in xylene solution. An X-ray structural study of the cis isomer shows the CS groups to be in the bridging positions, but otherwise, its structure is nearly identical to that of cia-[(η-C5H5)Fe(CO)2]2. The cis isomer reacts with CH3OSO2F to give the compound, (η-C5H5)2Fe2(CSCH3)(CS)(CO)2+, with a methylated bridging thiocarbonyl group.

The synthesis and structure of 10,11-bistrifluoromethyl-i,o-bicyclo[7.2.2]trideca-10,12-diene. A highly strained inside-outside bicycloalkane derivative.

Abstract 10,11-Bistrifluoromethyl-i,o-bicyclo[7.2.2]trideca-10,12-diene has been prepared by the Diels-Alder addition of hexafluoro-2-butyne to cis, trans-cycloundeca-1,3-diene. Purification was accomplished via formation of an iron tricarbonyl complex whose structure was established via X-ray crystallography.

X-ray Diffraction and the Structure of Marine Natural Products

While the success of X-ray diffraction in the elucidation of molecular structure is well known to natural products chemists, the physical principles responsible for this success appear to be only dimly perceived. Various idiosyncratic views range from disgust at an approach that smacks of cheating to contentment with an expeditious way to secure structures. In spite of this wide range of relatively uninformed views, a single-crystal X-ray analysis is taken as the ultimate measure of molecular structure. Why should this be the case?