摘要:

AbstractThe most widely known electrophilic agents are protic acids and compounds with an electronsextet partial structure. Recent research has aimed at the development of new electrophilic reagents, with greater reactivity on the one hand and higher selectivity on the other, which would largely obviate the addition of Lewis acids (Friedel‐Crafts catalysts), and also allow control of the isomer ratio in reactions with ambivalent substrates. Compounds with “super‐leaving groups”, such as trifluoromethanesulfonate and fluorosulfate, have been demonstrated as most advantageous in this respect since they are sufficiently polarized or dissociated for reactions to take place even in the absence of Friedel‐Crafts catalysts. Heterocycles such as pyridones or imidazole are likewise suitable leaving groups; they are employed for their high selectivity, and also because they allow working under non‐aqueous

ISSN:0570-0833    

DOI:10.1002/anie.198001513

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractNumerous additions of carbocations to chloroolefins or acetylenes can be coupled with a solvolysis step when performed in a suitable acid; the products are variously substituted carboxylic acids, aldehydes, and ketones. Factors determining the success of these syntheses are the stability of the intermediate carbocations and suppression of the competing addition of protons to the unsaturated reaction component. Under the conditions of the Tscherniac‐Einhorn reaction, amidomethylation of chloroolefins and acetylenes,i.e.the introduction of acylaminomethyl groups, is shown not to involve a trigonal α‐chloro carbocation or a linear vinyl cation, but instead to proceedviaa cyclic oxazinium ion intermed

ISSN:0570-0833    

DOI:10.1002/anie.198001711

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe reaction of olefins with carbon monoxide and hydrogen to give aldehydes is referred to as hydroformylation (oxo reaction). As catalyst for this reaction rhodium is about three to four orders of magnitude more active than the more commonly employed cobalt. With special rhodium compounds,e.g.di‐ν‐chlorobis(ν‐1,5‐cyclooctadiene)dirhodium [RhCl(C8H12)]2, in the presence of chiral phosphanes, even asymmetric hydroformylations can be achieved; however, the enantiomeric purity of the products (20–30%) is not high enough for industrial‐sc

ISSN:0570-0833    

DOI:10.1002/anie.198001781

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe biological activity of 3‐phenylpropylamines is not exclusively determined by their structure. It could be demonstrated that the fungicidal activity of partially hydrogenated compounds of this class of substances is also substantially influenced by the conformation. An optimization of the conformational criteria—illustrated by many examples, yet constituting only a small number of those actually examined—afforded compounds with excellent properties,e.g. N‐[3‐(4‐tert‐butyl‐1‐cyclohexenyl)‐2‐methylpropyl]‐cis

ISSN:0570-0833    

DOI:10.1002/anie.198001841

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe specific properties of inorganic pigments result from an interplay of solid‐state properties, particle size, and particle shape. However, phenomena occurring at the pigment interfaces also have implications for the use of the pigment. The interrelations for individual classes of pigments are indicated, and two selected examples, namely transparent colored pigments and magnetic pigments, are subsequently discussed with particular attention being paid to industrial development

ISSN:0570-0833    

DOI:10.1002/anie.198001901

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198001971

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198001981

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198001991

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198002011

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198002021

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY