Aliphatic Iodides Research Articles

Photoredox-Nickel Dual-Catalyzed C-Alkylation of Secondary Nitroalkanes: Access to Sterically Hindered α-Tertiary Amines.

The preparation of tertiary nitroalkanes via the nickel-catalyzed alkylation of secondary nitroalkanes using aliphatic iodides is reported. Previously, catalytic access to this important class of nitroalkanes via alkylation has not been possible due to the inability of catalysts to overcome the steric demands of the products. However, we have now found that the use of a nickel catalyst in combination with a photoredox catalyst and light leads to much more active alkylation catalysts. These can now access tertiary nitroalkanes. The conditions are scalable as well as air and moisture tolerant. Importantly, reduction of the tertiary nitroalkane products allows rapid access to α-tertiary amines.

Nickel(0)‐Catalyzed Hydrocyanation of Terminal Allenes: A Regio‐ and Enantioselective Approach to Branched Allylic Nitriles

AbstractA highly branched regioselective nickel(0)‐catalyzed hydrocyanation of mono‐ and 1,1‐disubstituted allenes as well as an asymmetric hydrocyanation of 1,1‐disubstituted allenes are reported herein, giving access to branched tertiary and quaternary β,γ‐allylic nitriles. For the regioselective hydrocyanation of terminal allenes, a nickel(0)/Biphephos catalytic system applicable to a substrate scope containing functional groups such as ester, THP‐group, primary aliphatic iodide, and a free carboxylic acid, provides yields up to 96%. By applying a catalytic system of Ni(0)/TADDOL‐based bisphosphite catalyst to 1,1‐disubstituted allenes, branched quaternary allylic nitriles are obtained in yields up to 99% and enantioselectivities up to 86%. Both protocols take advantage of a manageable HCN source and evidence good atom economy. In addition, the reaction's synthesis utility is highlighted by gram‐scale reactions with subsequent assorted transformation of the nitrile group as well as alkylation of the tertiary nitriles in α‐position.magnified image

Rhodium-Catalyzed Anti-Markovnikov Transfer Hydroiodination of Terminal Alkynes.

A rhodium-catalyzed anti-Markovnikov hydroiodination of aromatic and aliphatic terminal alkynes is reported. Depending on the choice of ligand and substrate, either (E)- or (Z)-configured alkenyl iodides are obtained in high to exclusive isomeric purity. The reaction exhibits a broad substrate scope and high functional group tolerance, employing easily accessible or commercially available aliphatic iodides as HI surrogates through a shuttle process. The synthesized vinyl iodides were applied in several C-C and C-heteroatom bond-forming reactions with full retention of the stereoselectivity. The developed method could be used to significantly shorten the total synthesis of a marine cis-fatty acid. Additionally, initial deuterium-labeling experiments and stoichiometric reactions shed some light on the potential reaction mechanism.

Rhodium‐katalysierte Anti‐Markovnikov Hydroiodierung von Terminalen Alkinen**

AbstractWir beschreiben eine Rhodium‐katalysierte anti‐Markovnikov Hydroiodierung von terminalen aromatischen und aliphatischen Alkinen. Je nach Wahl des Liganden und Substrats werden entweder (E)‐ oder (Z)‐konfigurierte Alkenyliodide mit hoher bis ausschließlicher Isomerenreinheit erhalten. Die Reaktion weist ein breites Substratspektrum und eine hohe Toleranz gegenüber funktionellen Gruppen auf, wobei leicht zugängliche oder kommerziell erhältliche aliphatische Iodide als HI‐Äquivalent via einem Shuttle‐Prozess verwendet werden. Die synthetisierten Vinyliodide wurden in mehreren Reaktionen zur Bildung von C−C und C−Heteroatom Bindungen unter vollständiger Beibehaltung der Stereoselektivität eingesetzt. Mit der entwickelten Methode konnte die Totalsynthese einer marinen cis‐Fettsäure deutlich verkürzt werden. Zusätzlich konnten mithilfe von Deuterium‐Markierungsexperimenten und stöchiometrischen Reaktionen erste Informationen über einen möglichen Reaktionsmechanismus erhalten werden.

Strong and Confined Acids Catalyze Asymmetric Intramolecular Hydroarylations of Unactivated Olefins with Indoles.

In recent years, several organocatalytic asymmetric hydroarylations of activated, electron-poor olefins with activated, electron-rich arenes have been described. In contrast, only a few approaches that can handle unactivated, electronically neutral olefins have been reported and invariably require transition metal catalysts. Here we show how an efficient and highly enantioselective catalytic asymmetric intramolecular hydroarylation of aliphatic and aromatic olefins with indoles can be realized using strong and confined IDPi Brønsted acid catalysts. This unprecedented transformation is enabled by tertiary carbocation formation and establishes quaternary stereogenic centers in excellent enantioselectivity and with a broad substrate scope that includes an aliphatic iodide, an azide, and an alkyl boronate, which can be further elaborated into bioactive molecules.

Photo-induced copper-catalyzed alkynylation and amination of remote unactivated C(sp3)-H bonds.

A method for remote radical C–H alkynylation and amination of diverse aliphatic alcohols has been developed. The reaction features a copper nucleophile complex formed in situ as a photocatalyst, which reduces the silicon-tethered aliphatic iodide to an alkyl radical to initiate 1,n-hydrogen atom transfer. Unactivated secondary and tertiary C–H bonds at β, γ, and δ positions can be functionalized in a predictable manner.

Nickel-Catalyzed Formal Aminocarbonylation of Unactivated Alkyl Iodides with Isocyanides.

Herein, we disclose a Ni-catalyzed formal aminocarbonylation of primary and secondary unactivated aliphatic iodides with isocyanides to afford alkyl amide, which proceeds via the selective monomigratory insertion of isocyanides with alkyl iodides, subsequent β-hydride elimination, and hydrolysis process. The reaction features wide functional group tolerance under mild conditions. Additionally, the selective, one-pot hydrolysis of reaction mixture under acid conditions allows for expedient synthesis of the corresponding alkyl carboxylic acid.

A Convergent Radical Based Route to Trifluoromethyl Ketones and to α,β-Unsaturated Trifluoromethyl Ketones

A convergent synthesis of trifluoromethyl ketones and α,β-unsaturated trifluoromethyl ketones is described, starting with aliphatic iodides and dithiocarbonates (xanthates) and exploiting both the α- and β-fragmentations of a sulfonyl radical. The transformation initially furnishes the ketones in a masked enol carbonate form, from which they can be easily regenerated.

ChemInform Abstract: Palladium‐Catalyzed Cross‐Coupling of PhSeSnBu3 with Aryl and Alkyl Halides in Ionic Liquids: A Practical Synthetic Method of Diorganyl Selenides.

AbstractThe Pd‐catalyzed reaction of phenylselenylstannane (II) with a wide variety of aromatic and aliphatic iodides and bromides proceeds smoothly in a room temperature ionic liquid to give the corresponding phenyl organyl selenides in good yields.

ChemInform Abstract: Efficient Copper‐Catalyzed C—S Cross‐Coupling of Heterocyclic Thiols with Aryl Iodides.

AbstractA wide range of heterocyclic thiones or thiols are reacting with the aromatic and aliphatic iodides at the S‐site exclusively to afford the thioethers with high yields.

One-carbon extrusion from a tetraazafulvalene. Isolation of aldehydes and a study of their origin.

Reaction of imidazolylidene-derived enetetramine 2 with aliphatic iodides and bromides (and with aryl iodides bearing alkene-containing side-chains in the ortho-position) leads to formation of aliphatic aldehydes through an unprecedented extrusion of a one-carbon unit from the enetetramine. An intermediate 2-alkylimidazoline 24 is proposed, where the alkyl group derives from the substrate; this imidazoline undergoes further reaction in situ to afford the observed aldehydes on acidic workup. Modified substrates were designed and prepared to probe the chemistry of the alkylimidazoline adducts and provided extensive information on the chemistry of the adducts.

A catalytic process based on sequential ortho-alkylation and vinylation of ortho-alkylaryl iodides via palladacycles

A new synthesis of vinylarenes selectively substituted in both their ortho positions with different alkyl groups is reported. The reaction occurs starting from ortho-alkyl substituted iodoarenes which are caused to react with aliphatic iodides, terminal olefins, K 2CO 3, AcOK and Pd(OAc) 2 in a one-pot reaction consisting of a series of elementary steps controlled by palladium in its oxidation states 0, II and IV. A correct balance of all the steps involved is required to obtain a catalytic reaction.

Synthesis of aryl 3‐(2‐imidazolyl)propyl ketones

AbstractThe approach to the title compounds was via lithiation‐substitution of N‐methyl or N‐(triphenylmethyl)‐imidazole by some iodo ketals. 4‐Chloro‐4′‐halobutyrophenones (halo = F, Cl, Br) were converted by sodium iodide to the corresponding aliphatic iodides which were subsequently ketalized with ethylene glycol to provide the corresponding iodo ketals. Lithiation of either 1‐methyl‐ or 1‐(triphenylmethyl)imid‐azole with N‐butyllithium generated the corresponding 2‐lithioimidazoles, in situ, which were then reacted with these iodo ketals to form the corresponding C‐2 substituted imidazoles. Dilute aqueous acid hydrolysis released the ketone from the ketal. For N‐triphenylmethyl protected imidazoles, the triphenylmethyl group was also hydrolyzed to give triphenylmethanol and 3‐(2‐imidazolyl)propyl 4‐haloaryl ketones. These N‐unsubstituted imidazolyl ketones can be alkylated independently with triphenylmethyl chloride to form the corresponding N‐triphenylmethyl imidazole derivatives.

ChemInform Abstract: 4‐(Difluoroiodo)tricyclene, an Isolable Compound of Type RIF2 from an Aliphatic Iodide.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

4-(Difluoroiodo)tricyclene, an isolable compound of type RIF2 from an aliphatic iodide

The synthesis, characterisation and reactivity are reported for the title compound which is the first isolable compound of type RIF2 from an aliphatic iodide.

Cyclopalladated 2-t-butyl-4,4-dimethyl-2-oxazoline: its preparation, and use in the functionalisation of a non-activated carbon-hydrogen bond

Activation and functionalisation of one of the methyl groups of pivalic acid can be achieved through cyclopalladation of its 4,4-dimethyloxazoline derivative. This reaction gives a separable mixture of dinuclear and trinuclear species. The dimeric complex undergoes insertion of methyl vinyl ketone and of carbon monoxide, but is alkylated by aliphatic iodides, thereby providing a new route to homologated tertiary carboxylic acids.

Effects of reaction conditions on rates of incorporation of no‐carrier added F‐18 fluoride into several organic compounds

AbstractApparent rate constants (fractional incorporation per minute per mole of organic reactant) were determined for reaction of no‐carrier added F‐18 fluoride with several aliphatic and aromatic substrates in acetonitrile or DMSO. No large differences were seen between tetraethylammonium and potassium Kryptofix‐2,2,2 as supporting cation. Three hexose derivatives with triflate or cyclic sulfate leaving groups all gave apparent rate constants (obtained by dividing fractional incorporation by time in minutes and by molar concentration of reactant) near 0.4 at 23° and 5 at 55°. An aliphatic iodide reacted ten times more slowly. Aromatic substrates tested showed a wide range of rate constants from >50 at 23° (isotope exchange in 2,4‐dinitrofluorobenzene) to 0.6 at 134° (p‐nitroacetophenone).

Halogen abstraction studies. II. Free-radical abstraction of iodine from aliphatic iodides. Evidence to support anchimeric assistance by neighboring halogen in homolytic reactions

Halogen abstraction studies. II. Free-radical abstraction of iodine from aliphatic iodides. Evidence to support anchimeric assistance by neighboring halogen in homolytic reactions

Primary Process in the Photolysis of Alkyl Iodides

RECENTLY, Kasper and Pimental1 have detected stimulated emission from the transition I(5p2P½) → I(5p2P3/2) + hν (1.315µ) resulting from the flash photodissociation of methyl and trifluoromethyl iodides. This provided the first direct observation of electronically excited iodine atoms produced from the photolysis of alkyl iodides. A spectral analysis of methyl iodide by Porret and Goodeve2 had previously indicated that I(52P½) should be predominantly produced on the photolysis of this compound. Furthermore, these authors pointed out the close similarity between the spectra of the lower aliphatic iodides. The work described in this communication, which utilized kinetic spectroscopy in the vacuum ultra-violet region of the spectrum, confirms the work of Kasper and Pimental and extends the observations to ethyl, propyl and butyl iodides. Preliminary observations on the photolysis of hydrogen iodide are also reported here.

376. The relative reactivities of the aliphatic iodides. The interaction of alkyl iodides with sodium guaiacoxide in ethyl-alcoholic solution

The first page of this article is displayed as the abstract.