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Cyclopentadiene Derivatives (cyclopentadiene + derivative)
Selected AbstractsLewis Acid Mediated Reactions of Zirconacyclopentadienes with Aldehydes: One-Pot Synthetic Route to Indene and Cyclopentadiene Derivatives from Aldehydes and Benzyne or Alkynes.CHEMINFORM, Issue 6 2003Changjia Zhao Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Dialkenylation of Carbonyl Groups by Alkenyllithium Compounds: Formation of Cyclopentadiene Derivatives by the Reaction of 1,4-Dilithio-1,3-dienes with Ketones and Aldehydes.CHEMINFORM, Issue 34 2001Zhenfeng Xi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Intramolecular Reactions in Pseudo-Geminally Substituted [2.2]Paracyclophanes,CHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2007Lidija Bondarenko Dr. Abstract A selection of pseudo-geminally substituted [2.2]paracyclophanes, the alkynes 6, 7, 10, 11,a, and 11,b and the alkenes 8 and 9 were prepared for the study of intraannular reactions between functional groups in direct juxtaposition. Whereas 9 and 10 provide the corresponding cyclobutane and cyclobutene derivatives on irradiation (12 and 13, respectively), the bis-alkynes 7 and 11,b do not lead to a cyclobutadiene intermediate. In the latter case the "half-closed" butadiene derivative 17 was isolated. A Paterno,Büchi reaction took place on irradiation of 8 and 6, although the oxetene intermediate 21 produced in the second example did not survive the reaction conditions (ring-opening to 22). Bromine addition to 9, 10, and 7 occurred with high stereoselectivity (formation of the dibromides 27, 30, and 33, respectively), and is rationalized by postulating the formation of the cationic intermediates 26, 29, and 32, respectively. To study the interaction of a carbocation with a facing triple bond, the alcohol 34 was prepared from 6. On acid treatment ring closure to the triply-bridged phane 38 took place, accompanied by the hydration of the triple bond to the ketoalcohol 37. In an interesting intraannular [2+3]cycloaddition reaction the bis-acetylene 11,a, on treatment with n -butyl lithium, provided the cyclopentadiene derivative 42. That the two triple bonds of a pseudo-geminal diacetylene can engage in a cyclization reaction leading to the cyclopentadienone complex 44 was also shown by treating 11,b with iron pentacarbonyl. [source] Gold Catalysis: Anellated Heterocycles and Dependency of the Reaction Pathway on the Tether LengthADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009A. Stephen Abstract A series of furan-yne substrates with an arylalkynylamide substructure were prepared and subjected to catalytic amounts of phosphanegold(I) complexes. With two carbon atoms in the tether between the arylalkynylamide and the furan subunits, the formation of benzoanellated heterocycles was observed, a number of interesting heterocyclic framworks could be accessed in this way. With three carbon atoms in the tether, the outcome was quite different, cyclopentadiene derivatives anellated to tetrahydropyridine rings were isolated. The two different pathways suggested are supported by calculations regarding the selectivity-determining step. [source] | ||||||||||