3-Ferrocenyl-3-(1-naphthyl)cyclopropene. Synthesis, structure, and chemical transformations

Abstract

Crystalline 3-ferrocenyl-3-(1-naphthyl)cyclopropene was prepared by dehydrobromination of Z-and E-2-bromo-l-ferrocenyl-l-(l-naphthyl)-cyclopropanes by ButOK in DMSO. The resulting compound and the starting Z-monobromocyclopropane were characterized by X-ray diffraction analysis. The obtained cyclopropene reacts with 1,3-diphenylisobenzofuran to give a [4+2J-cycloadduct. The small ring opens upon treatment with HBF4 etherate to afford isomeric Z-and E-prop-l-enes and 1-ferrocenyl-3//-berLzo[e]indene. Thermolysis of this cyclopropene results in the formation of l-ferrocenyl-gbH-benzo [e]indene. In all cases, opening of the small ring is accompanied by exclusive alkylation of the naphthalene moiety.

Thermally Induced Cyclopropene−Carbene Rearrangements: An Overview

“…Similar reactions have also been reported for 3-ferrocenyl-3-phenylcyclopropenes. − It is noticeable that, in almost all cases, the cyclopropenes described above are tetrasubstituted. The less substituted systems have not been widely studied or react in different ways; 1,3-diphenylcyclopropene, for example, undergoes rapid dimerization through an ene reaction even at below ambient temperature …”

“…Cyclization also occurs into heterocycles at the 3-position of the cyclopropene: 98,[101][102][103][104] In other cases, the intermediate may react further, in the following example by an ene reaction: 101 Similar reactions have also been reported for 3-ferrocenyl-3-phenylcyclopropenes. [105][106][107] It is notice-able that, in almost all cases, the cyclopropenes described above are tetrasubstituted. The less substituted systems have not been widely studied or react in different ways; 1,3-diphenylcyclopropene, for example, undergoes rapid dimerization through an ene reaction even at below ambient temperature.…”

4-(4-Nitrobenzyl)pyridine in Reaction with Diferrocenyl(methylthio)cyclopropenylium Iodide

“…The X-ray diffraction data confirmed the chemical structure of compound 6. The length of the double C=C bond in the cyclopropene ring was equal to 1.307(6) Å and the lengths of the single C-C bonds, 1.479(6) Å; the acute angle at C(3) of the vertex of the threemembered ring was equal to 52.7(3)° [3,9]. The lengths of the C-Fe and C-C bonds in the ferrocenyl substituents as well as the geometric parameters of the ferrocene sandwiches are close to the standard values [9].…”

“…A conceivable mechanism of formation of compounds 8a,b is presented in Scheme 3: The reaction involves the initial attack of a carbanion species 10 on the ferrocenyl-substituted carbon atom of the three-membered ring resulting in unstable [9] 1,3-diferrocenylcyclopropene 11. Opening of its small ring into a vinylcarbene intermediate 12 is followed by an intramolecular transformation leading to the isomeric diferrocenylbutadienes 8a and 8b.…”

3-cyclobutyl-3-ferrocenylcyclopropene and 3-cyclobutylidene-3-ferrocenylpropyne Synthesis and chemical properties

“…l,l-Dibromo-2-cyclobntyl-2-ferrocenylcyclopropane (6) was prepared from alkene 8 according to a known procedure. Is Reduction of dibromide 6 was performed as described previouslyS; the reaction afforded cyclopropane 10 and monobromide 9 (a 4 : 1 mixture of Z and E isomers).…”