Ring-opening of cyclic ethers with carbon–carbon bond formation by Grignard reagents

Copolymerization of Ethylene with Functionalized 1,1-Disubstituted Olefins Using a Fluorenylamido-Ligated Titanium Catalyst

Considering the sustainability of material development, coordination polymerization catalysts effective for 1,1-disubstituted olefins are receiving a great deal of attention because they can introduce a variety of plant-derived comonomers, such as β-pinene and limonene, into polyolefins. However, due to their sterically encumbered property, incorporating these monomers is difficult. Herein, we succeeded in the copolymerization of ethylene with various hydroxy- or siloxy-substituted vinylidenes using a fluorenylamido-ligated titanium catalyst-MMAO system. This is the first example of ethylene/polar 1,1-disubstituted olefins' copolymerization using an early transition metal catalyst system. The polymerization proceeded at room temperature without pressurizing ethylene, and high-molecular-weight, functionalized polyethylene was obtained. The obtained copolymer showed a reduced water contact angle compared with that of the ethylene/isobutene copolymer, demonstrating the increment in hydrophilicity by hydroxy groups.

CF3SO2Na-Mediated Five-Component Carbonylation of Triarylboroxines with TMSCF3 and THF/LiOH/NaI to Give Aroyloxyalkyl Iodides

Herein, we developed an efficient and transition-metal-free multicomponent coupling reaction for the synthesis of aroyloxyl alkyl iodides. In the reaction among 2,4,6-triarylboroxines, THF, TMSCF₃, LiOH, and NaI, five-component reactions could be precisely controlled by modulating CF₃SO₂Na, supplying one type of aroyloxyl alkyl iodides in moderate to high yields. The reaction exhibits good functional group tolerance and a wide substrate scope and can be easily transformed into other useful compounds. The mechanism is proposed on the basis of the control experiments.

Nickel-Catalyzed Carbonylative Synthesis of Functionalized Alkyl Iodides

Functionalized alkyl iodides are important compounds in organic chemistry and biology. In this communication, we developed an interesting nickel-catalyzed carbonylative synthesis of functionalized alkyl iodides from aryl iodides and ethers. With Mo(CO)₆ as the solid CO source, both cyclic and acyclic ethers were activated, which is also a challenging topic in organic synthesis. Functionalized alkyl iodides were prepared in moderate to excellent yields with outstanding functional group tolerance. Besides the high value of the obtained products, all the atoms from the starting materials were incorporated in the final products and the reaction had high atom efficiency as well.

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Nickel-catalyzed carbonylative synthesis of functionalized alkyl iodides

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With Mo(CO)₆ as the solid CO source, carbonylative ether activation

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Good yields of functionalized alkyl iodides

Synthetic Study toward the Total Synthesis of Taxezopidines A and B

A concise synthetic approach to construct the [6,8,6]-tricyclic core of taxezopidines A and B, which contains a synthetically challenging bridged bicyclo[5.3.1]undecane ring system bearing most of the desired functionalized groups and stereocenters, has been established. This approach features a diastereoselective type II intramolecular Diels-Alder furan reaction. The stereochemistry of the acetoxy group at the allylic position of the dienophile alkene group, such as in 6a, was found to be critical for achieving the desired highly diastereoselective outcome.

Electron-Catalyzed Coupling of Magnesium Amides with Aryl Iodides

An electron was found to catalyze the coupling of magnesium diarylamides with aryl iodides giving triarylamines through a radical-anion intermediate. The transformation requires no transition metal catalysts or additives, and a wide array of products are formed in good-to-excellent yields.

Unexpected lateral-lithiation-induced alkylative ring opening of tetrahydrofurans in deep eutectic solvents: synthesis of functionalised primary alcohols

o-Tolyl-substituted tetrahydrofurans undergo highly regioselective ring opening with the concomitant formation of new C-C bonds as the result of a lateral lithiation reaction. This reaction provides a new method for the synthesis of functionalised primary alcohols and can be run directly in protic eutectic mixtures as benign reaction media at 0 °C and under air, competitively with protonolysis.

Synthesis of 1,4-amino alcohols by Grignard reagent addition to THF and N-tosyliminobenzyliodinane

The synthesis of 1,4-amino alcohols from THF treated with N-tosyliminobenzyliodinane (PhINTs) followed by a Grignard reagent under mild reaction conditions at room temperature is described herein. Various Grignard reagents were shown to be compatible, furnishing the corresponding 4-substituted-N-1,4-tosylamino alcohols in good to excellent yields. A partial or full detosylation of the N-tosyl-1,4-amino alcohol was observed in instances involving a sterically bulky Grignard reagent, leading to the deprotected 1,4-amino alcohol product in moderate to good yields. The synthetic utility of this protocol was demonstrated by the synthesis of a 5-substituted-N-tosyl-1,5-amino alcohol from THP and the conversion of two examples to their corresponding γ-lactam and pyrrolidine adducts.

Stereospecific cross-coupling reactions of aryl-substituted tetrahydrofurans, tetrahydropyrans, and lactones

The stereospecific ring-opening of O-heterocycles to provide acyclic alcohols and carboxylic acids with controlled formation of a new C-C bond is reported. These reactions provide new methods for synthesis of acyclic polyketide analogs with complex stereochemical arrays. Stereoselective synthesis of the cyclic template is utilized to control relative configuration; subsequent stereospecific nickel-catalyzed ring-opening affords the acyclic product. Aryl-substituted tetrahydrofurans and tetrahydropyrans undergo nickel-catalyzed Kumada-type coupling with a range of Grignard reagents to furnish acyclic alcohols with high diastereoselectivity. Enantioenriched lactones undergo Negishi-type cross-coupling with dimethylzinc to afford enantioenriched carboxylic acids. Application in a two-step enantioselective synthesis of an anti-dyslipidemia agent is demonstrated.