74339-76-7

Upstream product

• 52017-21-7 (3-bromo-3-methyl-n-butyl)benzene 
• 20669-47-0 indenyllithium 
• 95-13-6 1-indene 

Relevant academic research and scientific papers

Silver-catalyzed coupling reactions of alkyl halides with indenyllithiums

Coupling reactions of tertiary and secondary alkyl halides with indenyllithiums proceeded effectively in the presence of a catalytic amount of silver bromide to provide tertiary- and secondary-alkyl-substituted indene derivatives in good yields.

The Photochemical Generation of Isoindene and its Dimerization to Diastereomeric 1-(Indan-1-yl)indenes

Isoindene (1), generated by ultraviolet irradiation (Vycor filter, acetone solution) of 1,4-dihydro-1,4-methanonaphthalene-2,3-dione (14), is shown to undergo homodimerization at -60 deg C.This cycloaddition involves the intermolecular transfer of a hydrogen atom from one isoindene molecule to a second isoindene molecule in an pericyclic process.The gross structure of the resulting diastereomeric dimers was confirmed by synthesis from 1-bromoindan (25) and indenyl anion (26).The stereochemistry of the dimers was determined by comparing their dihydro derivatives (33) and (34) with authentic samples.The authentic samples were themselves prepared by cis hydrogenation (Pd/C) of (E)-2,2',3,3'-tetrahydro-1,1'-bi-1H-indenylidene (30) which yielded (34), and trans hydrogenation (Na/NH3) of (30) which formed (33) together with (34) (ratio 7:3).The (E) stereochemistry of (30), which was a critical feature in the stereochemical assignments to (33) and (34), was confirmed by n.O.e. studies on it and its (D4)derivative (32).Complete analysis of the proton, proton coupling was conducted on (32).This identified a 5J coupling between protons C3-H and C7-H which contributed a 6percent scalar coupling to the observed n.O.e. of 39percent at C7-H.This information allowed unambiguous stereochemical assignments to be made to (33).The chirality of 1,1'-bi-1H-indenyls (43) and (44), prepared by the radical coupling of 1H-inden-1-ylmagnesium bromide, was also determined by a similar hydrogenation process.

Synthesis of 1,1'-Biindenes and 3,3'-Biindenes

1,1'-Biindenes 2, conveniently prepared from indenyllithiums by treatment with copper(II) chloride, are quantitatively isomerized to the corresponding 3,3'-biindenes 3 by heating in triethylamine/pyridine.Both d,l and meso isomers of 2 react to form 3; the rate of reaction of the meso form, however, is substantially faster.

Synthesis of Pentafulvalene by Oxidative Coupling of Cyclopentadienide with Copper(II) Chloride

Starting with a nearly quantitative coupling of cyclononatetraenide 7 to 1,1'-dihydrononafulvalene 8 by means of AgBF4, a simple general synthetic concept for fulvalenes is outlined (Scheme 2), consisting in an oxidative coupling of 'Hueckel anions' like 2 and 7 to 1,1'-dihydrofulvalenes 10 with Ag(I) or Cu(II) salts, followed by deprotonation (->11) and oxidation (->12); it has been realised in the case of pentafulvalene (1; overall yield 61percent; Scheme 3) and 1,2:5,6-dibenzopentafulvalene (18; overall yield 66percent; Scheme 4).NMR-spectroscopic investigations show that 1 is a non-aromatic compound with strongly alternating bond-lengths, its ?-system being even more localised than that of simple pentafulvenes.In fact, 1 is extremely reactive in concentrated solutions above -50 deg C.Besides of polymerisations, Diels-Alder dimerisation 1->19 followed by a rearrangement 19->20 takes place (Scheme 5).

Etude de la polymerisation par voie cationique du bis(indenyl-1)d,l

Cationic polymerization of bis(indenyl-1)d,l was carried out in the presence of several types of initiators.The kinetic study of the polymerization of this monomer, initiated by TiCl4 at low temperature shows that the propagation rate is first order in bis(indenyl-1).Polymerization initiated by triflic acid at 50 deg C in benzene as a solvent results in low molecular weight poly bis(indenyl-1)d,l.The use of benzoyl hexafluoroantimonate leads to polymers of low polydispersity having an experimental DPn close to the theorical one.This seems to result from a fast and quantitative initiation step.