Available starting materials strategy based

An inqxMlant feature, characteristic of virtually all fiilvene-mediated strategies thus far described in the literature, is the relative ease with which the addends can be assembled from readily available starting materials prior to cycloaddition. (Customarily, a simple base-catalyzed condensation of an appropriate ketone substrate with a cyclopentadienide anion will suffice to provide good yields of the requisite fill-... 

Even the first thermotropic liquid crystals (cholesterol benzoate and cholesterol acetate) were chiral molecules, and their chiral mesophases were observed [2]. Here, the chirality is taken from the chiral pool. Because liquid crystals are needed in gram scales for physical research and technical applications, they should be prepared by short synthetic pathways using easily available starting materials. Thus, synthetic strategies based on the chiral pool are more often used than asymmetric synthesis or chiral separation techniques. 

Hydroamination can be defined as the simultaneous addition of the N—H bond across multiple bonds. Based on its 100% atom-economic and side-product-free nature, asymmetric hydroamination (AHA) serves as one of the most efficient strategies for the synthesis of chiral amines. Its easily available starting materials and nonhazardous nature make it a suitable industrial process in the synthesis of various pharmaceutical agents and synthetically important chemicals. 

An improved synthesis based on the same strategy was devised by Driguez and Henrissat [52]. These workers took advantage of the regiospecifically available position C-5 in 1,2-0-iso-propylidene-a-D-glucofuranurono-6,3-lactone (28). This easily accessible starting material was 0-sulfonylated with tosyl chloride followed by reduction of the lactone moiety and... 

The strategy (II) is based on less symmetrical imide building blocks such as the hydroxy acids 15a, b and 16a, b. Since 4-hydroxyphthalic acid is not commercially available relatively little work has been reported on monomers and PEIs derived from this starting material. For instance no PEIs containing 15a have been described so far. 

Some companies have started to announce the commercial availability of micro-reactor-based fuel processors in the past and present. Additionally, as more and more companies have the intention to explore the potential of microreaction technology for fuel conversion and small-scale electricity production, a commercial breakthrough may therefore be feasible in the future. Fast and efficient heat and mass transfer in microreactors and their operating strategies are prerequisites for such success. However, to obtain commercial breakthrough, a proof of principle in everyday life, i.e. long-term stability of catalysts under operation with real fuel and also of microreactor performance and material over several thousand hours, is still lacking - as for conventional fuel processors also. 

---