Phosphorus is essential for many reagents in organic synthesis, for ligands of late-transition metals and for phosphonoand phosphanylamino acids, the latter being important isosteres of amino acids. Similar to the Michaelis-Arbuzov and the Michaelis-Becker reaction the phospha-Michael addition, i. e. the addition of a phosphorus nucleophile to an acceptor-substituted alkene or alkyne, certainly represents one of the most versatile and powerful tools for the formation of P-C bonds since many different electrophiles and P nu-
The purpose of this paper is twofold: it presents recent innovation activities related to the implementation of LEDbased photochemical reaction technology at kilolab (20 L) and production (1000 L) scales at Syngenta Crop Protection AG in Munchwilen, Switzerland, and investigates the capital expenditure (CapEx) uncertainty estimation of photochemical lamps using Monte Carlo analysis. It was found that for the reaction system considered in this paper, depending on the photon rate measurement methodactinometry or radiometrythe CapEx uncertainty is expected to be within 15−30% at two standard deviations.
The cover picture shows a display of fireworks of fullerenes! Highly soluble dendritic branches with methanofullerene subunits at the periphery have been prepared by an efficient repetitive synthetic sequence that allows the dendritic growth of up to the fifth-generation derivative, which contains 16 peripheral fullerene subunits. Details are discussed in the article by J.-F. Nierengarten et al. on p. 85 ff.
We have discovered that alpha-[dimethyl(thexyl)silyl]acetaldehyde (= [dimethyl(1,1,2-trimethylpropyl)silyl]acetaldehyde; 31) has a strong, woody odor. Structural analysis has shown resemblance to known odorants with similar organoleptic properties. On the basis of structure-odor relationships, new and more-powerful woody and ambery sila odorants were prepared. Further derivatization led to a set of compounds with very interesting organoleptic properties. Selected chiral compounds were also prepared stereoselectively. The influence of the absolute configuration on the olfactory properties was in agreement with theoretical assumptions. We also designed other groups of organosilicon odorants. The compounds discovered can be obtained in a few simple steps from commercially available reagents, and may find application in the fragrance and flavor industry. Their structures provide interesting data for further research on structure-odor relationships.
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