Alkali Metals

Wardell, James L.

doi:10.1016/b978-008046518-0.00002-7

Cited by 68 publications

(17 citation statements)

References 369 publications

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“…Prior art has demonstrated that the organolithium derived from 1 undergoes clean, rapid 5-exo cyclization at temperatures above ∼ −20 °C in the presence of N,N,N ‘ N ‘-tetramethylethylenediamine (TMEDA) to deliver [(1-allyl-3-indolinyl)methyl]lithium in high yield . It might be anticipated that 1 would be a good substrate for PhLi-initiated cycloisomerization via the exchange-mediated sequence discussed above: not only is the initial exchange equilibrium between PhLi and 1 (eq 1) likely to be more favorable than that between PhLi and an alkyl iodide, , the [(1-allyl-3-indolinyl)methyl]lithium generated upon cyclization (eq 2) may be converted to product by exchange with either PhI (eq 3) or the starting material ( 1 ).…”

Section: Resultsmentioning

confidence: 99%

“…This novel cycloisomerization apparently involves three discrete steps as illustrated below (eqs 1−3) . Thus, the unsaturated alkyllithium initially generated by reversible exchange , between the iodide precursor and PhLi (eq 1) undergoes irreversible cyclization (eq 2) , prior to reconversion to a cyclic iodide and regeneration of PhLi (eq 3). Provided that the final equilibrium represented by eq 3 lies far to the right, the net isomerization is catalytic in PhLi.…”

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confidence: 99%

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Catalytic Cycloisomerization of Unsaturated Organoiodides

and

Carson

1998

J. Org. Chem.

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Catalytic quantities of phenyllithium (PhLi) have been found to initiate novel 5-exo cycloisomerization of a variety of structurally diverse unsaturated organoiodides. The isomerization reaction appears to be a process of broad synthetic utility for the preparation of iodomethyl-substituted five-membered rings. Primary, secondary, tertiary, or aryl iodides tethered to a suitably positioned carbon−carbon π-bond are converted cleanly to their cyclic isomers in good to excellent yield (i.e., 70−90%) by simply allowing a hydrocarbon−MTBE solution of the iodide to stand in the presence of a small quantity of PhLi at an appropriate temperature. The mechanism of the cycloisomerization was found to be substrate dependent: unsaturated aryl and primary alkyl iodides undergo isomerization via a three-step cascade (eqs 1−3) mediated by two reversible lithium−iodine exchange reactions bracketing an irreversible 5-exo cyclization of an unsaturated organolithium; unsaturated secondary and tertiary alkyl iodides apparently isomerize via a radical-mediated atom transfer process initiated by homolytic fragmentation of the ate-complex generated upon attack of PhLi on the iodine atom of the substrate.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Catalytic Cycloisomerization of Unsaturated Organoiodides

and

Carson

1998

J. Org. Chem.

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“…Organolithium compounds can undergo autoxidation toward formation of highly unstable organolithium peroxides, which upon fast interaction with another organolithium leads to the ultimate formation of lithium alkoxides. 1 Oxidation of RLi with ROOLi was proven by Müller and Töpel 2 in 1939 and used in several oxidative processes, 3 and the autoxidation of organolithiums further explored in preparation of alcohols. 4 …”

Section: Introductionmentioning

confidence: 99%

Pot-Economy Autooxidative Condensation of 2-Aryl-2-lithio-1,3-dithianes

et al. 2018

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The autoxidative condensation of 2-aryl-2-lithio-1,3-dithianes is here reported. Treatment of 2-aryl-1,3-dithianes with n-BuLi in the absence of any electrophile leads to condensation of three molecules of 1,3-dithianes and formation of highly functionalized α-thioether ketones orthothioesters in 51–89% yields upon air exposure. The method was further expanded to benzaldehyde dithioacetals, affording corresponding orthothioesters and α-thioether ketones in 48–97% yields. The experimental results combined with density functional theory studies support a mechanism triggered by the autoxidation of 2-aryl-2-lithio-1,3-dithianes to yield a highly reactive thioester that undergoes condensation with two other molecules of 2-aryl-2-lithio-1,3-dithiane.

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“…Lithium organometallic compounds are of special interest to organometallic chemists because of their widespread use in chemical laboratories and in industry applications. − Since the solid-state structures of the fundamental compounds [LiMe] 4 and [LiEt] 4 have been determined by X-ray diffraction experiments, , few structures of binary organolithium compounds (compounds formed between lithium cations and hydrocarbon anions without other neutral ligands) have been reported. Several years ago, Stalke et al were able to solve the single-crystal structures of the alkyllithium compounds [Li n Bu] 6 and [Li t Bu] 4 .…”

Section: Introductionmentioning

confidence: 99%

Solid-State Structures of Base-Free Indenyllithium and Fluorenylsodium

et al. 1999

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The solid-state structures of two important organometallic reagents, base-free indenyllithium and base-free fluorenylsodium, were determined by high-resolution X-ray powder diffraction experiments. Indenyllithium crystallizes as an infinite chain in the fashion of a “multidecker structure”, whereas fluorenylsodium forms the saltlike structure Na2[NaFl3], containing the novel trigonal [NaFl3]2- anion.

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Alkali Metals

Cited by 68 publications

References 369 publications

Catalytic Cycloisomerization of Unsaturated Organoiodides

Catalytic Cycloisomerization of Unsaturated Organoiodides

Pot-Economy Autooxidative Condensation of 2-Aryl-2-lithio-1,3-dithianes

Solid-State Structures of Base-Free Indenyllithium and Fluorenylsodium

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