Organolithium Reactions Research Articles

A simple preparation of iodoarenes, iodoalkenes and iodoalkynes by reaction of organolithiums with 2,2,2-trifluoro-1-iodoethane

Organolithium anions, generated either by deprotonation or lithium-bromine exchange, when quenched with 2,2,2-trifluoro-1-iodoethane produce cleanly the synthetically useful iodoarenes, iodoalkenes and iodoalkynes.

Regioselectivity of Addition of Organolithium Reagents to Enones: The Role of HMPA.

Regioselectivity of Addition of Organolithium Reagents to Enones: The Role of HMPA.

Origin of Solvent Acceleration in Organolithium Metal−Halogen Exchange Reactions

Quantum chemical studies (B3LYP) of metal−halogen exchange in the model system LiCHCH2/MeI are consistent with a T-shaped hypervalent iodine species of the type I(vinyl)(Me)(Li) being the transition state. In support of prior proposals by Collum and others that solvent acceleration of organolithium reactions does not result primarily from solvent-induced changes in the aggregation state of the lithium reagent, we find the solvent substantially accelerates the reaction even for a monomeric nonaggregated transition state. Introduction of a model solvent molecule suggests that solvent acceleration is the result of transition state stabilization by tighter binding of the solvent to lithium in the transition state as well as a destabilization of the reactant adduct, (vinylI)·(LiMe), relative to the separated reagents.

ChemInform Abstract: Reaction of Organolithiums with Fluoro‐N,N‐diallylanilines: A Benzyne‐ Mediated Anionic Cascade Leading to 3,4‐Disubstituted Indolines.

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.

Reaction of organolithiums with fluoro-N,N-diallylanilines: A benzyne-mediated anionic cascade leading to 3,4-disubstituted indolines

Regioselective ortho-lithiation of either 2-fluoro- ( 2) or 3-fluoro-N,N-diallylaniline ( 3) initiates an anionic cascade leading to an N-allyl-3,4-disubstituted indoline. The transformation involves loss of LiF from the ortho-lithiated species, regioselective intermolecular addition of the organolithium to the benzyne intermediate, and cyclization of the resulting [6-substituted-2-(N,N-diallylamino)phenyl]lithium.

アート錯体を用いる有機ハロゲン化合物の化学選択的メタル化反応

Ate complexes have been used for selective carbon-carbon bond forming reactions, however access to ate complexes with electrophilic functional groups has been limited. Main reason for the limitation lies on the preparative method of ate complexes, which includes usage of highly reactive organolithium and organomagnesium reagents. In order to develop a new strategy for the preparation of ate complexes directly from other ate complexes, we investigated halogen-metal exchange reactions of organic halides with ate complexes. The metalation is considered to be potentially chemoselective and wide spectrum of application in organic synthesis is expected. Cuprates and zincates turned out to be excellent metalating reagents of functionalized aryl and alkyl halides. Some chemoselective transformations were achieved using the metalation with ate complexes and modified zincates showed very specific reactivity toward intramolecular epoxide opening reaction.

Diastereoselective addition of organolithiums to new chiral hydrazones. Enantioselective synthesis of ( R)-coniine

The reactions of organolithiums with the new chiral hydrazones derived from ( S)-indoline-2-carboxylic acid afforded chiral hydrazines with high diastereoselectivities (up to 99% de) and the present method was utilized for the preparation of high optically pure ( R)-coniine (94% ee).

ChemInform Abstract: Novel Boron‐Nitrogen Containing Compounds from the Reaction of Organolithiums with Complexes Between Dimesitylfluoroborane and Six‐ or Five‐Membered Aza Aromatic Compounds.

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.

Enantiospecific and Stereoselective Synthesis of Polyhydroxylated Pyrrolidines and Indolizidines from trans-4-Hydroxy-L-proline.

We have developed a short, efficient, and stereoselective synthesis of polyhydroxylated pyrrolidine and indolizidine glycosidase inhibitors starting from 4-hydroxy-L-proline. The regio- and stereoselective hydroxylation of an N-Pf-4-oxoproline enolate and the stereoselective reduction of the resulting keto alcohol allowed us to introduce the cis diol present in the target compounds. The different side chains needed to complete the syntheses of the target compounds were introduced by reduction of the ester group of a substituted proline or by reaction of organolithium or organomagnesium reagents with the same group followed by stereoselective reduction of the resulting ketones. Hydrogenolysis of the alcohols thus obtained gave the hydrochlorides of the desired pyrrolidine glycosidase inhibitors, which were obtained in nine steps in overall yields greater than 50%. The indolizidine glycosidase inhibitor 8-epi-swainsonine was also prepared using this approach.

Novel boron–nitrogen containing compounds from the reaction of organolithiums with complexes between dimesitylfluoroborane and six- or five-membered aza aromatic compounds

Treatment of an ether solution of dimesitylfluoroborane–pyridine with organolithium reagents at –30 °C gives 1-dimesitylboryl-2-substituted 1,2-dihydropyridines, whereas similar treatment of dimesitylfluoroborane–thiazole or 1-substituted imidazoles gives products possessing novel 1, 4-diazonia-2,5-diboratacyclohexa-3,6-diene framework; the products from 1-substituted imidazoles are found to be in uniquely fixed conformation and partially optically resolvable.

Asymmetric 1,2-addition of organolithiums to aldimines catalyzed by chiral ligand

An asymmetric 1,2-addition reaction of organolithiums with imines 3, 7 was catalysed by a 0.05–1.3 equivalent of a chiral amino ether 2 to provide the corresponding optically active amines 4, 8.

Stereoselective Synthesis of (E) and (Z)-Vinylsilane by the Addition Reaction of Organometallic Reagent to Silyl-substituted Fischer-type Carbene Complex

Abstract The addition reaction of organolithium or Grignard reagents to pentacarbonyl[methoxy(methyldiphenylsilyl)carbene]molybdenum is examined, and either (E)- or (Z)-vinylsilanes are obtained with high selectivities depending on the reaction conditions.

Cerium(III) chloride remarkably increases the rates of formation and yields of ketones in the reaction of lithium carboxylates with organolithiums

The presence of CeCl 3 greatly increases the yield of ketones in the reaction of organolithiums with lithium carboxylates. The Ce III suppresses the enolization of the lithium carboxylate, previously unrecognized as a competing reaction except in special cases, and the formation of tertiary alcohols. One of the reasons for the latter effect is a surprising increase in the rate of addition of the organometallic to the lithium carboxylate in the presence of Ce III.

Charge-directed conjugate addition reactions of silylated .alpha.,.beta.-unsaturated amidate anions

A variety of N-substituted α-silylated-α,β-unsaturated amidate anions (2) have been found to be excellent Michael acceptors in charge-directed conjugate addition reactions with Grignard and organolithium reagents. The effects of olefin substitution, Si-substitution, N-substitution, and amidate counterion have been studied. Anionic acceptors may be prepared in situ by the addition of silylated vinyllithium reagents to isocyanates and then allowed to undergo conjugate addition reactions with subsequently added nucleophiles, but it was found to be more efficient to isolate neutral acceptors and regenerate the acceptor anion through the use of excess nucleophile. β-Substituted acceptors were found to react only with reactive organolithium reagents while a β,β-disubstituted acceptor failed to undergo conjugate addition reactions

Carbon-carbon bond formation by the reaction of organolithiums with α-lithiated cyclic enol ethers. Stereoselective synthesis of β- and γ-hydroxy di- and tri-substituted alkenes

Abstract α-Lithiation of dihydrofuran, benzofuran, and dihydropyran followed by treatment with various organolithiums stereoselectively produces in good yields the corresponding ring-opened ( E )-alkenyllithiums, i.e., ( E )-β(or γ)-hydroxy-ω-alkenyl-ω-lithioalkenes, the lithium atom of which can be readily replaced with H, D, or C groups, such as CO 2 and Me.

A one-pot synthesis of trifluoromethylated α,β-unsaturated esters

Trifluoromethylated α,β-unsaturated esters were convenientlysynthesized by reaction of organolithium compoundswith a fluorinated biscarbonylphosphonium salt which wasprepared in situ by acylation of the corresponding phosphoranewith trifluoroacetic anhydride.

ChemInform Abstract: A Michael Addition and Alkylation Sequence Using Methyl 2‐(Trimethylsilyl)propenoate. Stereoselective Synthesis of α‐Silyl Esters.

AbstractThe reaction of organolithiums, e.g. (I) or (V), with the title compound (II) leads to 1:1 adducts with high stereoselectivity.

Carbonyl addition reactions promoted by cerium reagents

Abstract

Conjugate addition reaction of organolithiums to naphthalenecarboxylates

Reaction of 2,6-di-tert-butyl-4-methoxyphenyl naphthalenecarboxylates with organolithiums provided the addition products to naphthalene nucleus in quantitative yield.

Asymmetric synthesis XVIII : Preparation of Chiral 1,2-diamines via the CN(R,S) Method. Application to the synthesis of an analogue of tetraponerine

The reaction of organo-lithium or cuprate derivatives towards the cyano group of 2-cyano-6-phenyloxazolopiperidine synthon 1 gives an imine which is reduced to a primary amine with a remarkable stereoselectivity. An application of this reaction to the synthesis of an analogue of tetraponerine is presented.