摘要:

AbstractBesides its technical meaning, the word “electronics” signifies another industrial revolution. The driving force behind this development is the very rapid progress in the field of integrated semiconductor circuits. An ever‐increasing number of structures of ever‐decreasing size must be accommodated on the same surface of the semiconductor crystal. This trend towards miniaturization embraces not only the integrated circuit but also its mounting panel, the printed circuit board; integrated circuits with 65 536 storage spaces,i.e.more than 100 000 individual functions, on a semiconductor die of less than 1 cm2are already standard today in industry. This micro‐world, the potential of which can hardly be fully appreciated even today, has a direct appeal to all those of scientific inclination. However, the role of chemistry in the creation of this world becomes clear only on closer examination of the manufacturing processes: no mechanical tool is fine enough and no machine is sufficiently precise and rapid to work out complicated structures in the micron range with the required perfection. Chemistry first made possible the mass production of electronic components and consequently their widespread use today, and it is chemistry which will also play a decisive role in the future. Whether in the field of photoresists for the production of printed circuit boards with conductor widths of less than 100 μm, or in overcoming the 1 μm barrier in the manufacture of semiconductors using electron beam‐ and X‐ray‐resists, photochemistry, radiation chemistry, and polymer chemistry will have to develop new manufacturing processes and provide industrially uti

ISSN:0570-0833    

DOI:10.1002/anie.198204553

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractMultibridged [2n] cyclophanes comprise a novel class of aromatic compounds, in which two benzene rings are connected by three up to a maximum of six ethano bridges. Compared to classical nonannelated arenes, their most distinct chemical property is the ease with which, particularly the higher‐bridged homologs, take part in addition reactions (Diels‐Alder additions, hydrogenations, and ionic additions). On the other hand, the typical regenerative behavior of aromatic molecules is not fully suppressed in the [2n]cyclophanes as evidenced by such typical electrophilic aromatic substitution reactions as bromination, Friedel‐Crafts acylation, and nitration. Besides these reactions in which the benzene rings are either destroyed or retained, reactions at and with the ethano bridges,e.g.their cleavage, isomerization, and functionalization can also

ISSN:0570-0833    

DOI:10.1002/anie.198204691

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe present day importance of cyclopentenone derivatives in preparative organic chemistry and especially in natural product chemistry is demonstrated by the stereoselective synthesis of substituted and annelated cyclopentanone derivatives. It has been found that 4‐oxo‐2‐cyclopentenyl acetate (“4‐acetoxy‐2‐cyclopenten‐1‐one”) can be used in many reactions as a substitute for cyclopentadienone, which is itself too unstable to be isolated. A large variety of polyfunctionalized cyclopentanone derivatives, as well as carbocyclic and heterocyclic annelation products, can thus be obtained in a simple way. Various stereoselective transformations of the adducts so formed are presented, using the total synthesis of brefeldin A—a typical natural product of this series—as example. Several methods for the synthesis of 4‐oxo‐2‐cyclopentenyl acetate are outlined and, in addition, the more important methods for the enantioselective synthesis of other 4‐substituted 2

ISSN:0570-0833    

DOI:10.1002/anie.198204801

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractUp to about 15 years ago compounds with a skeleton of phosphorus chains or rings were regarded as “exotic” in the field of nonmetal chemistry. Aside from a number of examples of molecules with two P atoms directly bonded to each other and a few sporadically discovered monocyclic ring compounds, only solids of undefined composition and structure were known. Since then the state of our knowledge in this sector has made considerable progress: between PH3and its derivatives on the one hand, and the high‐molecular modifications of elementary phosphorus on the other, an unexpected variety of well defined compounds have been discovered, showing many similarities to the analogous compounds of carbon. However, surprises can still occur even with “small” phosphorus‐containing molecules, as shown by the likewise recently discovered field of phosphorus three‐membered r

ISSN:0570-0833    

DOI:10.1002/anie.198204921

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractCyclic peptides containing biologically active hormone sequences are suitable models for studying conformation‐activity relationships. In such models the usual flexibility of peptide chains is reduced by their cyclic arrangement. However, conformational analysis of such systems by experimental means is possible only if a single conformer predominates at equilibrium, and criteria for this are put forward. NMR spectroscopic methods, including many recent advances, are discussed in relation to their ability to contribute to peptide conformational analysi

ISSN:0570-0833    

DOI:10.1002/anie.198205121

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198205242

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198205252

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198205261

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1982, 1322. DOI:10.1002/anie.198213220

ISSN:0570-0833    

DOI:10.1002/anie.198205271

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198205281

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY