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Complete Regio (complete + regio)

Distribution by Scientific Domains
Chemistry100%
Distribution within Chemistry
General & Introductory Chemistry50%

Selected Abstracts

Complete Regio- and Stereoselective Construction of Highly Substituted Silyl Enol Ethers by Three-Component Coupling,

ANGEWANDTE CHEMIE, Issue 39 2010
Dr. Akira Tsubouchi
Drei Komponenten zur totalen Kontrolle: Dreifach substituierte Silylenolether wurden durch Dreikomponentenkupplung von ,,,-ungesättigten ,-Silylketonen, Organokupferreagentien und organischen Halogeniden vollständig regio- und stereoselektiv synthetisiert (siehe Schema). Die Reaktion verläuft über eine 1,3-Wanderung der Silylgruppe unter Bildung von cyclischen Silicat-Zwischenstufen, die die Konfiguration der Silylenolether festlegen. [source]

Use of some aryl and heteroaryl nitrilimines and nitrones in the synthesis of spiroheterocycles

JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2004
Eva Jedlovská
1,3-Dipolar cycloadditions of C-(5-nitro-2-furyl)- N -methyl nitrilimine (2a), C -(5-nitro-2-furyl)- N -phenyl nitrilimine (2b), C -4-nitrophenyl- N -methyl nitrilimine (2c) and C,N -diphenyl nitrilimine (2d) with 1-R-substituted 3,3-methylene-5,5-dimethylpyrrolidin-2-ones (1a-d) where R is H, acetyl, 1,1-dimethylethoxycarbonyl and 1-methylethenyl proceed with complete regioselectivity in good yields to afford 1,3,7-trisubstituted-6-oxo-8,8-dimethyl-1,2,7-triazaspiro[4,4]non-2-enes (5a-g) exclusively. Cycloaddition of C -(5-nitro-2-furyl)- N -phenylnitrone (3b) to the exocyclic double bond of the dipolarophile 1a proceeds to 2-phenyl-3-(5-nitro-2-furyl)-6-oxo-8,8-dimethyl-1-oxa-2,7-diazaspiro[4,4]nonane (7) with complete regio- and stereoselectivity. [source]

ChemInform Abstract: Amine-Promoted Synthesis of Vinyl Aziridines.

CHEMINFORM, Issue 38 2010
Alan Armstrong
Abstract A new method to prepare synthetically important vinyl aziridines proceeds with complete regio- and stereoselectivity. [source]

[8+2] and [8+3] Cyclization Reactions of Alkenyl Carbenes and 8-Azaheptafulvenes: Direct Access to Tetrahydro-1-azaazulene and Cyclohepta[b]pyridinone Derivatives

CHEMISTRY - AN ASIAN JOURNAL, Issue 4 2008
José Barluenga Prof.
Abstract The reactivity of Fischer alkenyl carbenes toward 8-azaheptafulvenes is examined. Alkenyl carbenes react with 8-azaheptafulvenes with complete regio- and stereoselectivity through formal [8+3] and [8+2] heterocyclization reactions, which show an unprecedented dependence on the C, substituent at the alkenyl carbene complex. Thus, the formal [8+3] heterocyclization reaction is completely favored in carbene complexes that bear a coordinating moiety to give tetrahydrocyclohepta[b]pyridin-2-ones. Otherwise, alkenyl carbenes that lack appropriate coordinating groups undergo a formal [8+2] cyclization with 8-azaheptafulvenes to give compounds that bear a tetrahydroazaazulene structure. A likely mechanism for these reactions would follow well-established models and would involve a 1,4-addition/cyclization in the case of the [8+2] cyclization or a 1,2-addition/[1,2] shift,metal-promoted cyclization for the [8+3] reaction. The presence of a coordinating moiety in the carbene would favor the [1,2] metal shift through transition-state stabilization to lead to the [8+3] product. All these processes provide an entry into the tetrahydroazaazulene and cycloheptapyridone frameworks present in the structure of biologically active molecules. Se ha estudiado la reactividad de alquenilcarbenos de Fischer con 8-azaheptafulvenos. Los alquenilcarbenos reaccionan con 8-azaheptafulvenos a través de reacciones de heterociclación formales [8+3] y [8+2] con completa regioselectividad y estereoselectividad, mostrando una dependencia del sustituyente C, del complejo alquenilcarbeno sin precedentes. Así, en los complejos carbeno que contienen un resto coordinante la reacción de heterociclación formal [8+3] se favorece completamente para dar tetrahidrociclohepta[b]piridin-2-onas. Por otra parte, los alquenilcarbenos que carecen de grupos coordinantes apropiados, experimentan una ciclación formal [8+2] con los 8-azaheptafulvenos para dar compuestos con estructura de tetrahidroazuleno. Un mecanismo probable para estas reacciones se fundamenta en modelos bien establecidos e implica una adición 1,4/ciclación en el caso de la ciclación [8+2] o una adición 1,2/ciclación promovida por una migración 1,2 del metal en el caso de la reacción [8+3]. La presencia de un resto coordinante en el carbeno favorece la migración 1,2 del metal a través de una estabilización del estado de transición, conduciendo al producto [8+3]. Todos estos procesos representan una vía de acceso a los esqueletos de tetrahidroazuleno y cicloheptapiridona presentes en la estructura de moléculas biológicamente activas. [source]