Remarkable Nucleophilic Addition to and Ring Breaking of the Cycloheptatrienyl Ligand in Reactions of [μ-(1−3-η):(4−7-η)-Cycloheptatrienyl]tricarbonylirontricarbonylmanganese and -rhenium with Aryllithium Reagents

Abstract

The reactions of [μ-(1−3-η):(4−7-η)-cycloheptatrienyl]tricarbonylirontricarbonylmanganese, [MnFe{μ-(1−3-η):(4−7-η)-C7H7}(CO)6] (1) with 2 molar equiv of aryllithium reagent, ArLi (Ar = C6H5, o-, m-, p-CH3C6H4), in ether at low temperature gave acylmetalate intermediates, followed by alkylation with Et3OBF4 in aqueous solution at 0 °C to afford the four novel ring-opened olefin-coordinated tricarbonylirontricarbonylmanganese complexes [MnFe{C8H7(OC2H5)Ar}(CO)6] (3, Ar = C6H5; 4, Ar = o-CH3C6H4; 5, Ar = m-CH3C6H4; 6, Ar = p-CH3C6H4). Analogous reactions of [μ-(1−3-η):(4−7-η)-cycloheptatrienyl]tricarbonylirontricarbonylrhenium, [ReFe{μ-(1−3-η):(4−7-η)-C7H7)}(CO)6] (2), with ArLi (Ar = C6H5, o-, m-CH3C6H4, p-CF3C6H4) gave the corresponding products [ReFe{C8H7(OC2H5)Ar}(CO)6] (7, Ar = C6H5; 8, Ar = o-CH3C6H4; 9, Ar = m-CH3C6H4; 10, Ar = p-CF3C6H4). The structures of 4 and 10 have been established by single-crystal X-ray diffraction studies.

Hydrocarbyl Ligand Transformations on Heterobimetallic Complexes

“…The bridging cycloheptatrienyl ligand in complexes 258 undergoes nucleophilic attack with aryllithium reagents and then electrophilic attack, with Et 3 O + BF 4 - , to give the ring-opened conjugated μ-octatetraene complexes shown in Scheme . The structures of some examples of these complexes were established by single-crystal X-ray diffraction studies. ,

138 Cycloheptatrienyl Ring Opening and Formation of an Octatetraene Complex on Group 7−Iron Complexes

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Cyclooctatetraene (COT)-Coordinated Diiron Carbene Complexes and Their Remarkable Thermolysis Reactions

“…Although a mechanism for the formation of the products 10 , 12 , 14 , 16 , and 18 and products 11 , 13 , 15 , 17 , and 19 has not yet been fully established, it seems possible via a metalcyclobutane intermediate (a) or a chelated carbene intermediate (b) (Scheme ). The former was formed by a [2 + 2] cycloaddition, similar to that of the ring-opened polyene complexes [MFe{C 8 H 7 (OC 2 H 5 )Ar}(CO) 6 ] (M = Mn, Re). , For such an intermediate (a), a H shift from the N atom of the anilino to the C-1 position of the COT ring accompanied by the dissociation of the Fe−C(9) bond to form the CN double bond and subsequent abstraction of one CO molecule generated from the decomposition of the starting compound or an intermediate could occur to produce the C 8 ring addition product 10 (or 12 , 14 , 16 , and 18 ). Of particular interest is the formation of the seven-membered ring compounds 11 , 13 , 15 , 17 , and 19 , which could be via an intermediate (b), namely a chelated diiron carbene complex.…”

Studies on Thermolysis of Isomerized Products of Olefin-Coordinated Alkoxycarbene Iron Complexes. Novel Thermolytic Products and Their Structures

“…The considerable interest in the synthesis, structure, and chemistry of alkene-coordinated transition-metal carbene complexes stems largely from the fact that they are important intermediates in various reactions of transition-metal carbene complexes with alkenes. − In recent years, olefin-coordinated transition-metal carbene and carbyne complexes and/or their isomerized products have been examined widely; a great number of the olefin-coordinated transition-metal carbene complexes and/or their isomerized products were synthesized, and a series of novel isomerizations of olefin ligands have been observed by the reactions of olefin-ligated transition-metal carbonyls with aryllithium reagents followed by alkylation with alkylating reagents in our laboratory. − However, only very little is known 4b,11 about the reactivity of these novel olefin- coordinated metal carbene and carbyne complexes and their isomerized products. We are now interested in examining the reactivity of these isomerized metal carbene complexes.…”