Palladium(0)‐Catalyzed [2σ + 2π] Cycloadditions Methylenecyclopropane to Alkenes

Binger, Paul; Schuchardt, Ulf

doi:10.1002/anie.197702492

Cited by 56 publications

(23 citation statements)

References 11 publications

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“…No obvious trend was noted among those structurally diverse NHCs that delivered the desired reactivity. At first, formation of 3 was assumed as a result from typical MCP activation by Ni 0 , either from Ni 0 residue or unexpected in situ Ni II reduction during catalyst synthesis . However, control experiments using Ni 0 showed that 3 aa could not be formed under our mild reaction conditions (entry 14).…”

Section: Methodsmentioning

confidence: 95%

NHC/Nickel(II)‐Catalyzed [3+2] Cross‐Dimerization of Unactivated Olefins and Methylenecyclopropanes

Huang

2020

Angewandte Chemie

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Cross‐dimerization of a methylenecyclopropane (1) and an unactivated alkene (2) with typical hydroalkenylation reactivity was observed for the first time by using a [NHC‐Ni(allyl)]BArF catalyst (NHC=N‐heterocyclic carbene). Results show that the C−C cleavage of 1 did not involve a Ni0 oxidative addition, which was crucial in former systems. Thus the method reported here emerges as a complementary method for attaining highly chemo‐ and regioselective synthesis of methylenecyclopentanes (3) with broad scope. An efficient NHC/NiII‐catalyzed rearrangement of 1 leads to the convergent synthesis of 3 in the presence of 2.

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Section: Methodsmentioning

confidence: 95%

NHC/Nickel(II)‐Catalyzed [3+2] Cross‐Dimerization of Unactivated Olefins and Methylenecyclopropanes

Huang

2020

Angewandte Chemie

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“…~ spectroscopy. Similarly, reaction of the cis-and trans-2,3-d i met h y i met hy lenecyclo pro panes [ Mo2(CO),( q -C5Me5)2J and AgBF, in CHtClz gave respectively the syn,syn ( 6 ) and syn,ariti complex (7). The pentamethylcyclopentadienyl cations (6) and (7) obtained in these reactions were found to be contaminated with variable amounts of [Mo(CO),-(q-CSMe5)][BF4] presumably formed by competitive capture with…”

Section: C(l)-mentioning

confidence: 96%

Reactions of co-ordinated ligands. Part 30. The transformation of methylenecyclopropanes into cationic η⁴-trimethylenemethanemolybdenum complexes, reactions with nucleophilic reagents, and the molecular structure of [Mo{η⁴-C(CH₂)₃}(CO)₂(η-C₅Me₅)][BF₄]

Allen¹,

Barnes²,

Green³

et al. 1984

J. Chem. Soc., Dalton Trans.

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Reaction of [Mo~(CO),(~-C,M~,)~] with methylenecyclopropane and AgBF, in CH2CI2 affords the cationic trimethylenemethane complex [Mo{q4-C(CH2) 3)( CO) 2(q-C5Me5)] [B F, ] . Methylenecyclopropane and 2,2-dimethylmethylenecyclopropane react with [Mo( NCMe),(CO),(q-C,H,)][ BF4][BF,] confirmed that ring opening of methylenecyclopropane had occurred. The complex crystallises in the centrosymmetric orthorhombic space group Pbca with a = 12.822(2), b = 12.31 1 (3), c = 22.660(4) A, and Z = 8 ion pairs. The structure has been solved by conventional methods and refined by fullmatrix least squares to R = 0.0674 for 2 747 observed reflections at 268 f 1 K. In the cation the trimethylenemethane ligand adopts an orientation that is syn with respect to the OC-Mo-CO angle. It is pyramidal with the CH2 groups bent towards the molybdenum atom by an average of 12.4'. There is intramolecular congestion involving the C,Me5 and C(CH2)3 ligands that may contribute towards the observed asymmetric bonding of the former to the metal atom. Extended Huckel molecular-orbital calculations suggest that the observed syn stereochemistry is electronically preferred, and that the barrier to rotation of the T ~, -C ( C H ~) ~ ligand relative to a Mo(CO),(q-C,H,)fragment is high. The stereochemistry of the ring-opening reaction is disrotatory-out as exemplified by the conversion of cisand trans-2,3-dimethylmet hylenecyclopropane into syn,syn-dimet hyl and syn,anti-dimet hyl-trimethylenemethane complexes. The reaction of these cationic q4-trimethylenemethane complexes with the nucleophiles BH4 -, OH-, CuMe,-, and SPh-affords q3-allylic complexes derived from attack on the peripheral carbons.to giveMethylenec>clopropanes react with compounds of Fe', Rh', Ir', Pt ", and Pt' to form simple q2-bonded alkene complexes in which the three-membered ring remains i n t a ~t . ~. ~ However, these small-ring compounds are also known to undergo transition-metal-mediated reactions where carbon-carbon cleavage occurs. This is illustrated by the reaction of [Fez-(CO),] with methylene-2-phenylcyciopropane forming tricarbonyl( q4-trimet hylenephenylmet hane)iron, a detailed study with deuterium-labelled methylene-2-phenylcyclopropane showing that a distotatory-out ring-opening reaction occurs. Furthermore, a recent study of the chloropalladation reactions of methylenecyclopropanes carrying alkyl substituents on the three-membered ring showed that cleavage of the 2.3-0 bond occurred in a disrotatory manner. Ring cleavage also occurs in the palladium(0)-catalysed cycloaddition reactions of methylenecyclopropanes, although the question as to whether these reactions involve q4-trimethylenemethane complexes remains to be answered. We had previously observed that [ M o ( C O ) ~( ~-C , M ~, ) ] + reacts with methylenecyclopropane to form the first cationic q4-bonded trimethylenemethane complex, and this paper describes a detailed study of this reaction.$ Prepared by protonation (HBF,-Et20) of [MoM~(CO)~(T&H~)] dissolved in CHzCIz followed by reaction with MeCN.'j

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“…After their seminal report, Inoue and co-workers were able to demonstrate in 1979 that methylenecyclopropanes, containing highly reactive double bonds, can be converted into five-membered lactones in a catalytic fashion using a system comprised of [Pd(dba) 2 ] and PPh 3 (4:1) under forcing conditions (40 bar CO 2 , 130 C) [17]. Based on earlier reports on the reaction of methylenecyclopropanes and alkenes [68], the reaction was proposed to proceed similarly via intermediate trimethylenemethane-palladium complexes which react with CO 2 in a [3 + 2] cycloaddition.…”

Section: Palladium-catalyzed Reactionsmentioning

confidence: 99%

Transition Metal-Catalyzed Carboxylation of Organic Substrates with Carbon Dioxide

Brill

Lazreg

Cazin

et al. 2015

Topics in Organometallic Chemistry

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The development of sustainable chemical processes is a long-standing challenge. Carbon dioxide represents a renewable C1 building block for organic synthesis and industrial applications as an alternative to other common feedstocks which are based on natural gas, petroleum oil, or coal. Apart from the advantages associated with the nontoxicity and abundance of CO 2 , its utilization further enables the reduction in its atmospheric content, which contributes significantly to the greenhouse effect. Although widespread application of CO 2 in organic synthesis -even on an industrial scale -will not be able to fully compensate for the steadily increasing atmospheric quantities produced (mainly by the combustion of fuels), ecological and economical factors make its usage highly desirable. Therefore, tremendous efforts toward activation and utilization of CO 2 have been made by the scientific community over the last 30 years, and, as a result, the number of highly efficient transition metal-catalyzed CO 2 -incorporative reactions has increased dramatically, especially within the last decade. The achievements in the development of sustainable and economic chemical processes for the carboxylation of organic molecules with CO 2 are presented in detail in this chapter.

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Palladium(0)‐Catalyzed [2σ + 2π] Cycloadditions Methylenecyclopropane to Alkenes

Cited by 56 publications

References 11 publications

NHC/Nickel(II)‐Catalyzed [3+2] Cross‐Dimerization of Unactivated Olefins and Methylenecyclopropanes

NHC/Nickel(II)‐Catalyzed [3+2] Cross‐Dimerization of Unactivated Olefins and Methylenecyclopropanes

Reactions of co-ordinated ligands. Part 30. The transformation of methylenecyclopropanes into cationic η⁴-trimethylenemethanemolybdenum complexes, reactions with nucleophilic reagents, and the molecular structure of [Mo{η⁴-C(CH₂)₃}(CO)₂(η-C₅Me₅)][BF₄]

Transition Metal-Catalyzed Carboxylation of Organic Substrates with Carbon Dioxide

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Palladium(0)‐Catalyzed [2σ + 2π] Cycloadditions Methylenecyclopropane to Alkenes

Cited by 56 publications

References 11 publications

NHC/Nickel(II)‐Catalyzed [3+2] Cross‐Dimerization of Unactivated Olefins and Methylenecyclopropanes

NHC/Nickel(II)‐Catalyzed [3+2] Cross‐Dimerization of Unactivated Olefins and Methylenecyclopropanes

Reactions of co-ordinated ligands. Part 30. The transformation of methylenecyclopropanes into cationic η4-trimethylenemethanemolybdenum complexes, reactions with nucleophilic reagents, and the molecular structure of [Mo{η4-C(CH2)3}(CO)2(η-C5Me5)][BF4]

Transition Metal-Catalyzed Carboxylation of Organic Substrates with Carbon Dioxide

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Reactions of co-ordinated ligands. Part 30. The transformation of methylenecyclopropanes into cationic η⁴-trimethylenemethanemolybdenum complexes, reactions with nucleophilic reagents, and the molecular structure of [Mo{η⁴-C(CH₂)₃}(CO)₂(η-C₅Me₅)][BF₄]