20258-77-9Relevant academic research and scientific papers
Synthesis and characterization of 1- and 2-(ω-alken-1-yl)indenes, their lithium salts and dichlorozirconium(IV) complexes
Schumann, Herbert,Karasiak, Dirk F.,Muehle, Stefan H.,Halterman, Ronald L.,Kaminsky, Walter,Weingarten, Ulrich
, p. 356 - 372 (2007/10/03)
A series of new 1-, 2-, and multi-substituted indenes has been synthesized and characterized. The reaction of indenyl lithium or 4,7-dimethylindenyl lithium with alkenyl bromides yielded a mixture of 1- and 3-allylindene (1), 3-(3-buten-1-yl)indene (2), 3-(4-penten-1-yl)indene (3), 3-allyl-4,7-dimethylindene (4), 3-(3-buten-1-yl)-4,7-dimethylindene (5), as well as 3-(4-penten-1-yl)-4,7-dimethylindene (6). The 2-substituted indenes 2-allylindene (7), 2-(3-buten-1-yl)indene (8), 2-(4-penten-1-yl)indene (9), 2-allyl-4,7-dimethylindene (10), 2-(3-buten-1-yl)-4,7-dimethylindene (11), and 2-(4-penten-1-yl)-4,7-dimethylindene (12) were prepared by PdCl2(DPPF) or NiCl2(DPPE) catalyzed cross-coupling reactions of the appropriate Grignard reagents with 2-bromoindene or 2-bromo-4,7-dimethylindene. Alkenylation of 3-methylindenyl lithium and 2,4,7-trimethylindenyl lithium produced 1-(3-buten-1-yl)-3-methylindene (13) or 1-(3-buten-1-yl)-2,4,7-trimethylindene (14), respectively. The indene derivatives 1-14 react with n-butyl lithium in hexane yielding the corresponding lithium salts 1a-14a. Zirconium tetrachloride reacts with 1a, 2a, 4a-6a and 11a-14a under formation of the corresponding bis(indenyl)zirconium dichloride complexes 1b, 2b, 4b-6b and 11b-14b. All compounds were characterized by elemental analysis, 1H and 13C{1H}-NMR spectroscopy and mass spectrometry, 5b and 12b also by single crystal X-ray structural analysis. 1b, 4b-6b and 11b-13b are active catalysts for the polymerization of ethene and propene.
Synthesis of the Benzotricyclooctane Ring System. Intramolecular Cycloaddition of Indene Derivatives
Padwa, Albert,Goldstein, Steven,Pulwer, Mitchell
, p. 3893 - 3902 (2007/10/02)
The photosensitized triplet reactions of several 1-allyl-substituted indenes have been studied.The triplet-sensitized irradiations gave benzotricyclo2,7>octanes in good yield by means of a novel intramolecular cycloaddition.The effect of substituents on the regioselectivity of the sensitized rearrangement was studied in some detail.With the simple 1-allyl-substituted isomer, 1,5-cyclization of the excited state is the preferred path.This mode of cyclization is favored on the basis of strain, radical stability, and entropy factors.We have found, however, that the normal closure predicted by the rule of five does not occur in the photosensitized irradiation of the 1-prenyl-substituted isomer.With this system, intramolecular cycloaddition gives rise to the benzotricyclooctane system.The diradical produced from the sensitized 1,4-cyclization path is long lived enough to allow internal disproportionation to complete with radical coupling.The facility with which the intramolecular indene photocycloadditions occur makes this type of approach particularly attractive for the synthesis of some unusual polycyclic ring compounds.
ALLYLSTANNANES AS ELECTROFUGAL PARTNERS IN ALLYLIC ALKYLATION
Trost, Barry M.,Keinan, Ehud
, p. 2595 - 2598 (2007/10/02)
Unsymmetrical allyl-allyl couplings occur between allylstannanes and allyl acetates catalyzed by palladium(0) and a novel direct coupling of an allyl acetate in the presence of a distannane and a palladium(0) catalyst is also possible.
