13377-46-3

Upstream product

• 498-66-8 norborn-2-ene 
• 75-11-6 diiodomethane 
• 498-66-8 norbornene 
• 14094-12-3 tert-butyl methyl sulfone 
• 25628-09-5 tetramethylammonium trifluoromethanesulphonate 
• 100-42-5 styrene 
• 70557-99-2 2-(iodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 
• 186581-53-3 diazomethane 
• 26986-63-0 2-Formyl-norbornan-p-toluolsulfonylhydrazon 
• 3635-95-8 exo-tricyclo<3.2.1.0^2,4>oct-6-ene 
• 917-54-4 methyllithium 

Relevant academic research and scientific papers

Nickel-Catalyzed Cyclopropanation with NMe4OTf and nBuLi

Nickel was identified as a catalyst for the cyclopropanation of unactivated olefins by using in situ generated lithiomethyl trimethylammonium triflate as a methylene donor. A mechanistic hypothesis is proposed in which the generation of a reactive nickel carbene explains several interesting observations. Additionally, our findings shed light on a report by Franzen and Wittig published in 1960 that had been retracted later owing to irreproducibility, and provide a rational basis for the systematic development of the reaction for preparative purposes as an alternative to diazomethane or Simmons-Smith conditions.

Mechanistic Studies on the Nickel-Catalyzed Cyclopropanation with Lithiomethyltrimethylammonium Triflate

We report here our mechanistic study of the previously published nickel-catalyzed cyclopropanation reaction using lithiomethyltrimethylammonium triflate as methylene donor. The cyclopropane yield is highly dependent on the olefin substrate and correlates well with the binding affinity of the olefin to Ni(0) as established elsewhere. On the basis of this observation, we developed a simplified mechanistic model that can explain several odd observations we found in our initial report. Most importantly, a binding equilibrium between the olefin substrate and phosphine ligand appears to govern the ratio between product formation and unproductive ylide decomposition in a side reaction.

Cyclopropanation of Terminal Alkenes through Sequential Atom-Transfer Radical Addition/1,3-Elimination

An operationally simple method to affect an atom-transfer radical addition of commercially available ICH2Bpin to terminal alkenes has been developed. The intermediate iodide can be transformed in a one-pot process into the corresponding cyclopropane upon treatment with a fluoride source. This method is highly selective for the cyclopropanation of unactivated terminal alkenes over non-terminal alkenes and electron-deficient alkenes. Due to the mildness of the procedure, a wide range of functional groups such as esters, amides, alcohols, ketones, and vinylic cyclopropanes are well tolerated.

Gold(I) Carbenoids: On-Demand Access to Gold(I) Carbenes in Solution

Chloromethylgold(I) complexes of phosphine, phosphite, and N-heterocyclic carbene ligands are easily synthesized by reaction of trimethylsilyldiazomethane with the corresponding gold chloride precursors. Activation of these gold(I) carbenoids with a variety of chloride scavengers promotes reactivity typical of metallocarbenes in solution, namely homocoupling to ethylene, olefin cyclopropanation, and Buchner ring expansion of benzene.

CYCLOPROPANATION

A method of preparing a cyclopropane ring-bearing compound of the formula (I) in which R1 and R2 are independently selected from C1-C10 alky], optionally substituted, or R1 and R2 together with the bonds linking them to the cyclopropane ring, form a monocyclic or bicyciic ring system, which may comprise at least one hetero-atom, comprising the reaction of a compound of formula (II) in which R1 and R2 have the significances hereinabove defined, with a compound of formula (III) in which X is selected a nucieofuge selected from halides and pseudohalides and Y is an electro flige selected from boranes and borates, in the presence of a metal catalyst complex selected from those that a useful for catalytic cyclopropanation and those useful for catalyzing Heck coupling. The method prov ides a particularly easy and non-hazardous method of cyclopropanation.

A palladium-catalyzed methylenation of olefins using halomethylboronate reagents

Methylenation of electron-rich olefins is a highly challenging reaction, for which we have developed a new methodology exploiting Pd-catalysis and halomethylboronate reagents, the latter replacing diazomethane and zinc carbenoids as methylene donors. Optimization of the reaction for norbornene and extension to several other olefins are reported, with reasonable-to-excellent yields of cyclopropanes in combination with β-H elimination products. Several mechanisms are plausible for this methylenation reaction.

Cine-Substitution in the Stille Coupling: Evidence for the Carbenoid Reactivity of sp3-gem-Organodimetallic Iodopalladio-trialkylstannylalkane Intermediates

Two complementary routes to sp3-gem-organodimetallic iodopalladio-trialkylstannanylalkanes are presented. Such intermediates have been proposed as Pd-carbenoid precursors in the Busacca-Farina cine-substitution mechanism in the Stille coupling. The decomposition of iodomethyltrialkylstannanes by Pd(0) catalysts was monitored by 1H, 2D, and 119Sn NMR. The formation of ethylene, trace formaldehyde, and iodotrialkylstannanes was detected. When the reaction was carried out in the presence of norbornene, the corresponding cyclopropane was produced in good yield. These observations are consistent with the intermediacy of a Pd-carbenoid species. sp3-gem-Organodimetallic iodopalladio-trialkylstannanylalkane complexes were also prepared under stoichiometric conditions via transmetalation from tin to Pd(II). Me3SnCH2Sn(CH2CH2CH2)3 reacted with [(D-t-BPF)PdI]+I-, yielding the (D-t-BPF)Pd(II)ICH2SnMe3 complex that dimerized to form ethylene and cyclopropanated norbornene. The carbenoid reactivity of iodopalladio-trialkylstannanylalkanes complexes validates the Busacca-Farina mechanism of the cine-substitution in the Stille coupling. Copyright

Conversion of non-activated alkenes into cyclopropanes with lithiated sulfones under nickel catalysis

Summary -Lithiated alkyl ierf-butyl sulfones convert alkenes into cyclopropane derivatives under nickel catalysis. The new reaction appears to differ from the known cyclopropanation reactions from both the stereochemical and the electronic points of view. Elsevier.

Stereodirecting Effect of a Substrate Methoxy Substituent on the Addition of Singlet Methylene to a Double Bond

The stereodirecting effects of substrate methoxy, hydroxy, methylthio, and methyl substituents were examined in the addition of 1:CH2 to the double bonds of substrates 1a-d.The carbene, generated by photolysis of CH2N2, inserted into the C-H bonds of solvent and substrate, added to the substrate double bond to give products 2a-d, and attacked the oxygen or sulfur atom of substrates 1a-c to produce ylide intermediates which underwent 2,3-sigmatropic rearrangement to give products 3a-c.A preference for addition syn to the methoxy group of substrate 1a was observed when the reaction was run in pentane solution (syn-2a/anti-2a, 1.14 +/- 0.02), while a preference for formation of anti-2a was observed in diethyl ether solution (syn-2a/anti-2a, 0.92 +/- 0.03).A preference for 1:CH2 addition anti to the substrate substituent was observed for substrates 1b-d in both pentane and ether solution.The effect of the methoxy substituent was also examined in the addition of 1:CH2 to syn-7-methoxynorbornene (5b).Explanations for the substituent effects are offered based on both steric hindrance and interaction between 1:CH2 and the substituent, including formation and subsequent reaction of the ylide intermediates.

Interaction of diazoalkanes with unsaturated compounds. 12. Stereochemistry of cyclopropanation of norbornenes with diazomethane in the presence of transition metal complexes

The stereochemistry of cyclopropanation of norbornenes with diazomethane in the presence of Cu, Pd, and Rh compounds has been studied.Stereoselectivity of the cyclopropanation depends on the nature of the transition metal and does not depend on its valent state or ligand environment.The reaction proceeds predominantly as exo-cycloaddition of the methylene fragment.The greatest amount of endo-isomer (up to 47 percent) is formed in cyclopropanation of norbornadiene and exo-tricyclo2,4>oct-6-ene in the presence of Cu and Rh compounds.