摘要:

AbstractTriphase catalysis (TC) has recently been introduced as a unique form of heterogeneous catalysis in which the catalyst and each of a pair of reactants are located in separate phases. Based on this concept, new synthetic methods have been developed for aqueous phase–organic phase reactions using a solid phase catalyst. Although it is only at an early stage of development, TC shows considerable potential for practical use. Our mechanistic understanding of these highly complex catalytic systems is at present very limited and detailed examination will be required before their relationship to phase‐transfer, micellar, and interfacial catalysis becomes cl

ISSN:0570-0833    

DOI:10.1002/anie.197904213

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractThe principle features of the biosynthesis of natural products have been elucidated during the past thirty years by the use of isotopic methods. It was discovered that large groups of natural products originate from the same biosynthetic precursor—the key building block. The conversion of key building blocks into biologically active natural products serves as a model for the development of more efficient syntheses in chemistry. In medicine, information about key building blocks permits the elucidation and therapy of metabolic disease

ISSN:0570-0833    

DOI:10.1002/anie.197904291

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractAn investigation of the effects of a controlled microenvironment on reactivity has been carried out by the synthesis and study in organized monolayers of surfactant molecules containing photochemically reactive chromophores. Reactions where substantial environmental effects have been observed include thecis‐transisomerization of olefins, ketone photoeliminations, ligand substitution processes, excimer and photodimer formation, and photoredox reactions. Both reactions occurring within the organized assemblies as well as interfacial phenomena have been investigated. Results obtained in these studies suggest possible extensions and applications for the development of new catalyst systems, biological models and controlled synthese

ISSN:0570-0833    

DOI:10.1002/anie.197904401

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractOrganic ions decompose in the field‐free regions of a mass spectrometer after a relatively well‐defined lifetime (t≈ 10−5s). This lifetime is very long compared with the time‐scale of molecular bond vibrations and consequently the excess internal energy (“non fixed” energy) present in the transition state for dissociation is comparable with that found in solution experiments. In general, only the energetically most favorable decay routes are able to compete. Moreover, information concerning kinetic energy release (T) accompanying unimolecular decomposition may be obtained from a consideration of the metastable peak for the process; these extremely valuable data are inaccessible to solution experiments because of the effects of collisions. The chemistry of ions may therefore be investigated conveniently by generating the ions of interest in a mass spectrometer and analyzing the reactions which occur in metastabl

ISSN:0570-0833    

DOI:10.1002/anie.197904511

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197904621

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197904631

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197904642

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197904661

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197904671

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197904681

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY