ISSN:0570-0833    

DOI:10.1002/anie.199413091

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe substitution of hydrogen by fluorine in organic compounds usually results in drastic changes in their properties. For isocyanides, for which fluorinated examples have only recently become available in preparative quantities, this substitution leads to a significantly increased reactivity and a tendency to polymerize, which, on one hand, makes their handling more difficult. On the other hand, this high reactivity makes the fluorinated isocyanides useful building blocks for the synthesis of compounds likeN‐trimethylformamide. Energetically favorable π*orbitals bestow excellent π‐acceptor properties towards low‐valent transition metal complexes, especially on the ligand trifluoromethyl isocyanide. The pronounced tendency of this ligand to bridge two metal atoms enables the formation of structural types that are not accessible with other π‐acceptor ligands. Thus it was possible to prepare [(Os3(CO)11(μ2‐CNCF3)2] (a) derivative of the hypothetical [Os(CO)13]) which may be considered as a model for an associative mechanism of ligand substitution at carbonyl clusters. In contrast to the well‐studied chemistry of trifluoromethyl isocyanide, that of the few other known fluorinated isocyanides is only now receiving attention. In particular the only recently synthesized trifluorovinyl isocyanide promises a rich chemistry as a result of its

ISSN:0570-0833    

DOI:10.1002/anie.199413151

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractBase‐induced elimination reactions have found wide application in the synthesis of strained alkenes. The method is often complicated by a competing process in which the incipient alkene is trapped by nucleophilic addition of the base. Recent studies have shown that the bi‐molecular side reactions can be avoided when bases such as potassiumtert‐but‐oxide are supported on an inert surface like silica gel and the reaction is carried out in vacuo. This vacuum gas‐solid reaction (VGSR) procedure has the additional advantage that very unstable species may be isolated under conditions that allow detailed studies of their physical and chemical properties. The scope of this procedure has been extended to include the use of fluoride salts supported on glass helices to effect the elimination of β‐halosilanes. The fluoride route to strained alkenes is particularly attractive since the reaction may be carried out at very moderate temperatures and the starting materials are readily available. This review describes the development of this vacuum gas‐phase procedure and its application in the synthesis and characterization of small‐ring alkenes and bicycloalkenes, including methylene‐cyclopropene, spiropentadiene, bicyclo‐propenyls, 1,2‐ and 1,3‐bridged cyclo‐propenes, and o

ISSN:0570-0833    

DOI:10.1002/anie.199413321

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199413451

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199413481

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199413511

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199413521

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199413541

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199413561

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199413591

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY