Rational Syntheses

Although a great deal of excitement has surrounded the use of ionic liquids as solvents for organic synthesis, the rational synthesis of inorganic and organometallic compounds in ionic liquids has remained largely unexplored. 

A rational synthesis of the parent compound 4 is by the condensation of 1-chloroethane-l, 2-bisfsulfcnyl chloride) (2) with bis(trimcthylsilyl)sulfur diimidc (3) in dichloromcthanc at high... 

The Vogel group has also developed rational synthesis of the above annulenones as well as of the other two possible isomers 2,8-14 and 3,9-methano[ 11 ]annulenone 15. 

The rational synthesis of 11 started from 4,5-benzocycloheptenone ethylene ketal 16 which was reduced to the dihydrocompound 17 with lithium in liquid ammonia. Cyclopropanation of the latter with dichlorocarbene then gave the adduct 18, the ketal oxygens of 7 7 presumably coordinating with the carbene and directing it... 

The rational synthesis of 3,8-methano[ 1 ljannulenone 12 started from 2-meth-oxy-l,4,5,8-tetrahydronaphthalene 25 which on reaction with dibromocarbene provided the bis-adduct 26. 

From the viewpoint of structural chemistry, structure and bonding lie at the heart of rational syntheses that have already contributed to many significant scientific advances in inorganic chemistry and material chemistry, and especially to the discovery of some functional materials. Naturally the first step to novel functional material is synthesis , and in many cases exploratory synthesis seems to be the only workable route to new compound. However, rational synthesis will surely make property-oriented exploration more fruitful and pleasing. 

The formation of most dithiocarbaminato complexes seems to be the result of serendipity and rational synthesis of such compounds has yet to be developed. There is much novel chemistry to be expected in this area. 

Duan, X. Lieber, C. M. 2005. Semiconductor nanowires Rational synthesis. In Dekker Encyclopedia of Nanoscience and Nanotechnology, edited by Schwarz J. A., Marcel Dekker, Inc., New York. 

Cyclocarbons All-Carbon Molecules through Rational Synthesis. Likely Intermediates in Fullerene Formation... 

The rational synthesis of peptide-based nanotubes by self-assembling of polypeptides into a supramolecular structure was demonstrated. This self-organization leads to peptide nanotubes, having channels of 0.8 nm in diameter and a few hundred nanometer long (68). The connectivity of the proteins in these nanotubes is provided by weak bonds, like hydrogen bonds. These structures benefit from the relative flexibility of the protein backbone, which does not exist in nanotubes of covalently bonded inorganic compounds. 

W. M. Xue, M. C. Kung, and H. H. Kung, Rational synthesis of asymmetric bicyclic siloxane, Chem. Commun. 2164 (2005). ([AQ] Author Please provide volume number in references [13], [14].)... 

Although the disconnection of the "strategic bonds" should be in principle the solution of choice in designing a rational synthesis of twistane (see below, 13.1.2), syntheses based in the disconnection of bonds other than those have also been... 

Therefore, a rational synthesis of caryophyllenes should be designed in such a way that after proceeding through a series of common intermediates at a given step they may offer the opportunity to exert a stereochemical control in the formation of the endocyclic double bond. In this context, the synthesis reported by Corey as early as 1964 [1] is still more efficient than more recent syntheses in which only one isomer (isocaryophyllene, lb) is formed [2] or that require parallel synthetic sequences which start from compounds which are only remotely related to each other [3]. 

The title of this session. Guided and Serendipitous Discovery (within the symposium. Approaches to Rational Synthesis of Pesticides) focuses attention on the nature of the discovery, rather than the outcome. The discovery of the avermectin family of compounds was by no means serendipitous those who were seeking found what they sought. It is the purpose of this paper to record the manner of the seeking and the manner... 

The above considerations show that the rational synthesis and structural characterization of new POMs remain a challenge. Nevertheless, the potentially attractive catalytic properties of such species are a strong motivation to undergo this kind of research. 

Only in the case of chlordiazepoxide can one speak in terms of goal-directed development here the intention was to find tranquillizing compounds in a new and patentable class of substances. In no case, however, was there a biochemical hypothesis concerning the illness or symptoms to be treated that would have led to the rational synthesis and development of appropriate pharmaceuticals. 

The precursor was prepared via a lengthy sequence involving the elaboration of a Reformatsky adduct. The cyclic product was obtained as a 1.2 1 mixture of cis and trans isomers.The presence of the fluorine atoms had no effect on the efficiency of the cyclisation reaction. A subsequent study [384] extended the range of cyclisations to include trifluoromethyl alkyl and alkenyl radicals (Eq. 157). Free radical cyclisation reactions therefore show considerable promise for the rational synthesis of fluorinated carbocycles. 

The isolation of [FesC(CO)12Br2]2- was fortuitous, and attempts at rational synthesis have not been successful. See ref. (24). 

Bicyclic cyclotrigermanes, thermolysis, 3, 793 Bicyclic imidazoles, via intramolecular C-H functionalizations, 10, 138 Bicyclic siloxanes, rational synthesis, 3, 655 Bicycloctasilane dianion, preparation, 3, 466468 Bicyclo[5.3.0]decadiene, via [5+2]-cycloadditions, 10, 613 Bicyclo[5,3,0]-decanes, via Pauson-Khand reaction, 11, 361 Bicyclononasilane anions, preparation, 3, 466-468 Bicyclo[3.3.0]-octanones, via carbonylative carbocyclization, 11, 427... 

Venkatasubbaiah, K., Bats, J. W., Rheingold, A. L., Jakle, F., Rational synthesis and complexation behavior of the bidentate lewis acid l,2-bis(chloromercury)ferrocene. Organometallics 2005, 24, 6043-6050. 

---