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  • 1
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Stannyl complexes ; Chromium complexes ; Anionic complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition Metal Stannyl Complexes, 7[1]. - Preparation of Carbene Complexes (π1-Arene)(CO)2CrCR2 by the Reaction of the Anionic Stannyl Complexes [(π1-Arene)(CO)2CrSnPh3]- with R2CX2 or [R2CX]YCarbene complexes (π1-arene)(CO)2Cr=CR2 are formed in substitution/elimination reactions from the anionic stannyl complexes K[(π1-arene)(CO)2CrSnPh3] [π1-arene=C6H6 (1a), 1,3,5-Me3C6H3 (1b), 1,2,4,5-Me4C6H2 (1c)] C6Me6 (1d) and organic dihalides R2CX2 containing activated C - X bonds or ionic halides [R2CX]Y. Bis(stannyl) complexes (π1-arene)(CO)2Cr(SnPh3)2 (3) and hydrido(stannyl)complexes (π1-arene)(CO)2Cr(H)SnPh3 are formed as byproducts due to the reaction of the eliminated Ph3SnCl with the anionic starting complexes or electron transfer reactions, respectively. The portion and ratio of the byproducts is largely influenced by the steric properties of both the (π1-arene)(CO)2Cr fragment and the organic halide. Pyridinylidene complexes 2) are only obtained from 2-chloro-N1-methylpyridinium tetrafluoroborat with 1a - c, but not with 1d. With the sterically less demanding halides [R2N=C(H)Cl]Cl [NR2=NMe2, (n=3, 4)] or 3,3-dichloro-1,2-diphenylcyclopropene the carbene complexes (π1-arene)(CO)2Cr=C(H)NR2 or are obtained with all employed π1-arene ligands.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2524-2545 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyfunctionalised Cyclohexanes from Dianhydroinositols. cis-l,3(1,4)-Inosadiamines from BenzeneThe preparative value of the dianhydroinositols 4 - 6, which are readily available from benzene, for the total synthesis of cis-1,4- and cis-1,3-disubstituted cyclohexanetetrols is demonstrated. With monovalent reagents (H2O, HI, NaN3, NH2NH2) the twofold epoxide opening proceeds regioselectively (1,4-disubstitution) yielding the muco- and chiro-cyclohexane derivatives 9, 17, and 26. With hydrazine and N,N′-dimethylhydrazine as 1,2-dinucleophiles the cis-1,3-inosadiamines 7g (5-epistreptamine) and 16g, j (2-epistreptamine, actinamine) are obtained from 4/5 in good yields (75 - 90%). From the less symmetrical 6, however, only the mixture of 25g (streptamine) and 27g is produced in modest yield (ca. 50%). The epoxide opening reactions starting from 4 - 6 are kinetically so similar that a selective opening is not possible.
    Notes: Die Brauchbarkeit der aus Benzol gut zugänglichen Dianhydroinosite 4 - 6 für die Totalsynthese cis-1,4- bzw. cis-1,3-disubstituierter Cyclohexantetrole wird exemplarisch belegt. Mit monovalenten Partnern (H2O, HI, NaN3, NH2NH2) erfolgt die zweifache Epoxidöffnung jeweils regioselektiv (1,4-Disubstitution) zu den muco-bzw. chiro-Cyclohexan-Derivaten 9, 17 und 26. Mit Hydrazin bzw. N,N′-Dimethylhydrazin als 1,2-Dinucleophilen lassen sich aus 4/5 in guten Ausbeuten (75 - 90%) die cis-1,3-Inosadiamine 7g (5-Epistreptamin) und 16g,j (2-Epistreptamin, Actinamin), aus dem weniger symmetrischen 6 in nur bescheidener Ausbeute (ca. 50%) ein Gemisch von 25% (Streptamin) und 27g herstellen. Die von 4 - 6 ausgehenden Epoxidöffnungen sind kinetisch so wenig differenziert, daß eine selektive Einfachöffnung nicht möglich ist.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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