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Carbocyclization Reactions (carbocyclization + reaction)
Selected AbstractsCo/C-Catalyzed Tandem Carbocyclization Reaction of 1,6-Diynes.CHEMINFORM, Issue 39 2003Sang Ick Lee Abstract For Abstract see ChemInform Abstract in Full Text. [source] Regiodivergent Ligand-Controlled Rhodium-Catalyzed [(2+2)+2] Carbocyclization Reactions with Alkyl Substituted Methyl Propiolates,ANGEWANDTE CHEMIE, Issue 33 2010Andrew Evans Prof. Man hat die Wahl: In der Titelreaktion lässt sich die selektive Bildung der zwei Regioisomere durch sorgfältige Wahl der Hilfsliganden steuern (siehe Schema). Entscheidend war der Befund, dass Reste von Silbersalzen aus der Salzmetathese des neutralen Komplexes einen starken Einfluss auf die Regio- und Diastereoselektivität haben. [source] [Rh(CO)2Cl]2 -Catalyzed Domino Reactions Involving Allylic Substitution and Subsequent Carbocyclization Reactions.CHEMINFORM, Issue 37 2005Brandon L. Ashfeld Abstract For Abstract see ChemInform Abstract in Full Text. [source] Diastereoselective Synthesis of Five- and Seven-Membered Rings by [2+2+1], [3+2], [3+2+2], and [4+3] Carbocyclization Reactions of ,-Substituted (Alkenyl)(methoxy)carbene Complexes with Methyl Ketone Lithium EnolatesCHEMISTRY - A EUROPEAN JOURNAL, Issue 17 2005José Barluenga Prof. Dr. Abstract ,-Substituted alkenylcarbene complexes react with methyl ketone lithium enolates to give different carbocyclization products depending on the structure of the lithium enolate, on the metal of the carbene complex, and on the reaction media. Thus, the reactions of aryl and alkyl methyl ketone lithium enolates with ,-substituted alkenyl chromium and tungsten carbene complexes in diethyl ether afford 1,3-cyclopentanediol derivatives derived from a formal [2+2+1] carbocyclization reaction. However, the lithium enolates of acetone and tungsten complexes furnish formal [3+2+2] carbocyclization products. In the case of alkynyl methyl ketone lithium enolates, competitive formal [2+2+1] and [3+2] carbocyclization reactions occur and 1,3-cyclopentanediol and 3-cyclopentenol derivatives are formed. Conversely, alkenyl methyl ketone lithium enolates react with alkenylcarbene complexes under the same reaction conditions to form 2-cycloheptenone derivatives by a formal [4+3] carbocyclization reaction. Finally, when the reaction was performed in the presence of a coordinating medium, the [3+2] carbocyclization pattern was observed independently of the nature of the methyl ketone lithium enolate used. Los complejos alquenilcarbeno , -sustituidos reaccionan con enolatos de litio de metil cetonas para dar diferentes productos de carbociclación dependiendo de la estructura del enolato de litio, del metal del complejo carbeno y del medio de reacción. Así, la reacción de enolatos de litio de aril y alquil metil cetonas con complejos alquenilcarbeno de cromo y wolframio , -sustituidos en dietil eter origina derivados de 1,3-ciclopentanodiol, derivados de una reacción de carbociclación formal [2+2+1]. Sin embargo, el enolato de litio de la acetona y complejos de wolframio dan lugar a productos de carbociclación formal [3+2+2]. En el caso de enolatos de litio de alquinil metil cetonas, se observa la formación de una mezcla de derivados de 1,3-ciclopentanodiol y 3-ciclopentenol derivados de reacciones de carbociclación formal [2+2+1] y [3+2] competitivas. Por el contrario, los enolatos de litio de alquenil metil cetonas reaccionan con complejos alquenilcarbeno en las mismas condiciones de reacción para generar derivados de 2-cicloheptenona a través de una reacción de carbociclación formal [4+3] Finalmente, cuando la reacción se lleva a cabo en presencia de PMDTA, un medio coordinante, se observa el modelo de carbociclación formal [3+2], independientemente de la naturaleza del enolato de litio utilizado. [source] | ||||||||||