Titanium-Catalyzed Rearrangement and Olefin-Exchange of Grignard Reagents<sup>1</sup>

Cooper, Glenn D.; Finkbeiner, Herman

doi:10.1021/jo01052a001

Cited by 85 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Convincing evidence of this assumption arises from results obtained in the alkylations with iPrMgBr. It is well known [28] that isopropylmagnesium bromide smoothly rearranges, even at low temperatures, to give n-propylmagnesium bromide in the presence of small amounts of TiCl 4 . In the reaction of iPrMgX with 1 aa and 1 ca (Table 3, entries 3 and 12, respectively) we only found the incorporation of the a-branched chain in the final products 2 aae and 2 cae.…”

Section: Grignard Reagent Itself a Fivefold Excess Of Rmentioning

confidence: 99%

Internal Lewis Acid Coordination as a Powerful Tool To Promote Highly Stereoselective Alkylation ofα-Alkyl-β-Hydroxy Ketones with Grignard Reagents

Bartoli¹,

Bellucci²,

Bosco³

et al. 1998

Chem. Eur. J.

View full text Add to dashboard Cite

An efficient and highly diastereoselective protocol is described for the alkylation of b-hydroxy ketones that contain an a-stereocenter. This method is based on the preliminary transformation of the b-hydroxy group into a titanium alcoholate by means of the facile transmetalation of the corresponding b-silyloxy derivative with TiCl 4 (Method A) or by reaction of the lithium alcoholate with TiCl 4 (Method B).On account of the strong internal coordinating action of the Lewis acid, this intermediate assumes a rigid half-chair conformation with the a-alkyl substituent in a pseudoaxial position. This geometrical arrangement facilitates the attack of the entering carbanion on the carbonylic function opposite to the asubstituent. The method uses simple Grignard reagents as the alkylating agents and allows the addition of a wide variety of carbon frameworks to the carbonyl function, including primary and secondary alkyl chains, arylic, alkynylic, vinylic, and benzylic moieties, with high efficiency and stereoselectivity.

show abstract

Section: Grignard Reagent Itself a Fivefold Excess Of Rmentioning

confidence: 99%

Internal Lewis Acid Coordination as a Powerful Tool To Promote Highly Stereoselective Alkylation ofα-Alkyl-β-Hydroxy Ketones with Grignard Reagents

Bartoli¹,

Bellucci²,

Bosco³

et al. 1998

Chem. Eur. J.

View full text Add to dashboard Cite

show abstract

“…To have a better insight on the reaction mechanism, Negishi performed the following two isomerization reactions: (1) (2-deuterioallyl)benzene (7) was treated first with a catalytic amount of 4 to give after two hours in THF at 60°C the corresponding E-(2-deuterio-1-propenyl)benzene (8) with >91% D incorporation on the C-2;…”

Section: Methodsmentioning

confidence: 99%

A Zirconium Promenade - An Efficient Tool in Organic Synthesis

Marek¹,

Chinkov²,

Levin³

2006

Synlett

View full text Add to dashboard Cite

show abstract

“…[13] This complication can be avoided by the use of shuttle catalysis and an early example was reportedi n1 962 by Cooper and Finkbeiner (Scheme 5). [14] They found that 1-pentene reactedw ith isopropylmagnesiumb romide in the presence of catalytic titanium chloridet oa fford n-pentylmagnesium bromide.I nt he process, propene is produced as aby-product and its volatility is aprobable driving force, although it is possible that it is less reactive towardshydromagnesiation.After trapping with formaldehyde, n-hexanolw as isolated in 45 %y ield. Later this reaction was also shown to be catalyzed by nickel, vanadium, zirconium, and iron complexes.…”

Section: Transfer Of Reactive Functionalitymentioning

confidence: 99%

Shuttle Catalysis—New Strategies in Organic Synthesis

Bhawal

Morandi

2017

Chemistry A European J

View full text Add to dashboard Cite

Shuttle catalysis has recently emerged as a powerful new concept that provides a platform for performing both functionalization and defunctionalization reactions. In this concept article, applications of shuttle catalysis as a novel strategy in organic synthesis are discussed. This includes using forward shuttle catalysis reactions for challenging bond-forming processes that avoid the use of hazardous chemicals. Shuttle catalysis also facilitates the transfer of reactive functionality as a route to procure a broad range of compounds using one simple procedure. Reverse shuttle catalysis reactions are also discussed as a method for the valorization of biomass and waste materials. Another area of interest, shuttle-catalysis-assisted reactions, wherein the transfer of a small molecule is utilized in a catalytic cycle, is also described. Possible future directions in this exciting new field are also suggested.

show abstract

Titanium-Catalyzed Rearrangement and Olefin-Exchange of Grignard Reagents¹

Cited by 85 publications

References 0 publications

Internal Lewis Acid Coordination as a Powerful Tool To Promote Highly Stereoselective Alkylation ofα-Alkyl-β-Hydroxy Ketones with Grignard Reagents

Internal Lewis Acid Coordination as a Powerful Tool To Promote Highly Stereoselective Alkylation ofα-Alkyl-β-Hydroxy Ketones with Grignard Reagents

A Zirconium Promenade - An Efficient Tool in Organic Synthesis

Shuttle Catalysis—New Strategies in Organic Synthesis

Contact Info

Product

Resources

About

Titanium-Catalyzed Rearrangement and Olefin-Exchange of Grignard Reagents1

Cited by 85 publications

References 0 publications

Internal Lewis Acid Coordination as a Powerful Tool To Promote Highly Stereoselective Alkylation ofα-Alkyl-β-Hydroxy Ketones with Grignard Reagents

Internal Lewis Acid Coordination as a Powerful Tool To Promote Highly Stereoselective Alkylation ofα-Alkyl-β-Hydroxy Ketones with Grignard Reagents

A Zirconium Promenade - An Efficient Tool in Organic Synthesis

Shuttle Catalysis—New Strategies in Organic Synthesis

Contact Info

Product

Resources

About

Titanium-Catalyzed Rearrangement and Olefin-Exchange of Grignard Reagents¹