摘要:

AbstractVarious structures have been proposed for the intermediates of electrophilic additions onto olefins; these include halonium ions, classical carbonium ions, π‐complexes (i.e. nonclassical carbonium ions), and π‐complexes with back‐coordination. It is shown here that it is impossible to use any one of these entities alone to explain all such electrophilic additions; the electrophile itself determines the nature of the transition state formed. Polar addition of hydrogen halides onto olefins appears to proceed via a classical carbonium ion which does not occur as the free ion but as an undissociated ion pair. Various other mechanisms have been excluded by studies reported here of the stereochemical course of such ad

ISSN:0570-0833    

DOI:10.1002/anie.196402451

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractIt is shown that carbonyl olefination, i.e. the reaction of carbonyl compounds with alkylidene phosphoranes, can be sterically controlled. In some cases cis‐olefins can be obtained by proper choice of the reaction conditions; trans‐olefins are formed only in the presence of suitable structural factors. These cis‐and trans‐olefination reactions have opened new, stereo‐specific routes to unsaturated and polyunsaturated fatty acids with differing positions and sequences of cis‐ and trans‐double bonds and to ω‐hydroxy and branched c

ISSN:0570-0833    

DOI:10.1002/anie.196402501

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractTetramethylurea is an excellent solvent for organic substances, particularly aromatic compounds. It is suitable as reactions. Being inert toward Grignard compounds, it is a useful solvent for reactions of the latter with compounds that are sparingly soluble in ether. Several industrially feasible syntheses of tetramethylurea are discussed.

ISSN:0570-0833    

DOI:10.1002/anie.196402601

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe reactions of t‐butyl peroxyesters with various classes of compounds in the presence of a catalytic amount of copper ions produce well‐defined acyloxy derivatives. This peroxyester reaction, discovered by Kharasch and Sosnovsky, can be used to effect one‐step oxidation of saturated and unsaturated hydrocarbons, alcohols, aldehydes, esters, ethers, sulfides, organosilicon compounds, etc. The reaction can be highly selective: in most cases only one specific carbon atom is attacked. However, with some ethers and, sulfides the reaction can take a more complex course, other products being formed in addition to the acyloxy derivatives. The mechanism of the reaction has been extensively investigated, and several concerted and chain mechanisms have been pro

ISSN:0570-0833    

DOI:10.1002/anie.196402691

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe methods described in the literature for the synthesis of aliphatic thioketones are examined critically in the light of the authors' own work; new practical methods of preparation are reported, and characteristic properties of thioketones are described.

ISSN:0570-0833    

DOI:10.1002/anie.196402771

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196402871

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196403061

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196403072

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196403082

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196403092

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY