Phosphoramidites: Privileged Ligands in Asymmetric Catalysis

Teichert, Johannes F.; Feringa, Ben L.

doi:10.1002/anie.200904948

Cited by 622 publications

(336 citation statements)

References 491 publications

Supporting

Mentioning

332

Contrasting

Unclassified

Order By: Relevance

“…Applying strictly the same reaction conditions, a similar study was conducted using only three of the many commercially available phosphoramidite ligands. 10 No improvement in activity, selectivity, or scope was thus achieved (5 examples, 8489% yield, 3870% ee). 11 Building on the observation that Crabtree's hydrogenation catalyst [(Cy 3 P)(C 6 H 5 N)Ir(cod)](PF 6 ) 3 may perform unexpected isomerization for certain olefinic substrates, 12 Mazet and coworkers have recently developed a protocol which enables the exclusive isomerization of a variety of primary allylic alcohols into aldehydes under very mild reaction conditions.…”

Section: ç Primary Allylic Alcoholsmentioning

confidence: 98%

Platinum Metals in the Catalytic Asymmetric Isomerization of Allylic Alcohols

Mantilli

Mazet

2011

Chemistry Letters

View full text Add to dashboard Cite

Past and recent advances in the metal-catalyzed asymmetric isomerization of allylic alcohols into carbonyl compounds are discussed in the present Highlight. Emphasis is placed on rhodium, ruthenium, and iridium; the only three metals that have proven successful to date for this most challenging transformation. Ç IntroductionThe metal-catalyzed asymmetric isomerization of primary and secondary allylic alcohols into the corresponding aldehydes and ketones®a reaction of both academic and industrial relevance®has attracted renewed interest in recent years. 1Because such transformations undergo refunctionalization upon isomerization, they are often described as internal redox processes and from a synthetic viewpoint, legitimately placed at the very top of the atom-economy scale (Scheme 1). 2Although a variety of transition metals displays interesting catalytic activity for the non-asymmetric isomerization of some allylic alcohols with TOF up to 62500, 3 the substrate generality remains a major limitation. In most cases, the catalytic activity tends to decrease as a function of the degree of substitution of the olefinic double bond and thus limits investigation of substrates with a prochiral double bond. Catalysts that are effective for the isomerization of primary allylic alcohols are less active for secondary allylic alcohols as is the converse. Furthermore, the lack of supporting organometallic chemistry and the limited number of thorough mechanistic studies using achiral catalysts constitute severe bottlenecks in the rationalized development of highly active and selective chiral catalysts for the related asymmetric isomerization reactions.The focus of the present Highlight is placed exclusively on chiral catalysts elaborated around rhodium, iridium, and ruthenium, three of the Platinum Metals which have been applied with various success to the asymmetric isomerization of primary and secondary allylic alcohols. Ç Primary Allylic AlcoholsThe asymmetric isomerization of primary allylic alcohols into chiral aldehydes is historically intimately linked to the related isomerization of allylic amines into chiral enamines. 46 The degree of refinement attained by this rhodium-catalyzed process in terms of activity, selectivity, generality, and practicality is exceptional and has helped defining standards of excellence; very few other catalytic asymmetric transformations have reached to date. In contrast, the asymmetric isomerization of allylic alcohols does not belong to this elite category. Because of the apparent similarity between both isomerization reactions, and the influence of the success story of the cationic [(binap)Rh] system for the isomerization of allylic amines, most of the subsequent catalysts have been designed using chiral bidentate phosphines and rhodium for the isomerization of primary allylic alcohols. The initial studies conducted in the early 80s' showed that [(binap)Rh(cod)]ClO 4 1 (cod: 1,5-cyclooctadiene) was also catalytically competent for the isomerization of primary allylic alcohols i...

show abstract

Section: ç Primary Allylic Alcoholsmentioning

confidence: 98%

Platinum Metals in the Catalytic Asymmetric Isomerization of Allylic Alcohols

Mantilli

Mazet

2011

Chemistry Letters

View full text Add to dashboard Cite

show abstract

“…62 We attempted to induce asymmetry through the use of an appropriate chiral ligand. Extensive investigations revealed that Feringa s phosphoramidite ligand 82 63 exhibited the best results in our study. Hence, we used the following optimized conditions: 80 (100 μmol), Pd 2 (dba) 3 ·CHCl 3 (2.5 mol %), ligand 82 (25 mol %), NaOAc (1.5 equiv.…”

mentioning

confidence: 62%

Synthetic Studies on Heteropolycyclic Natural Products: Strategies via Novel Reactions and Reactivities

Shimokawa¹,

Fukuyama

2017

J. Synth. Org. Chem. Jpn.

View full text Add to dashboard Cite

Five total syntheses of heteropolycyclic natural products, namely hyalodendrin, tryprostatins, spirotryprostatin A, the core of the stemofoline alkaloids, and hinckdentine A, are outlined. These syntheses share common characteristics; the sequences of transformations are facilitated through the development of new synthetic reactions and the discoveries of unknown molecular reactivities. Brief descriptions of new reactions, the mechanistic details of key transformations, and the resulting shortcuts and ef ciencies made possible in relation to the overall picture of these total syntheses are described.

show abstract

“…Among the challenges found in the stereoselective synthesis of organic molecules, it is included the development of low cost ligands and catalysts. [1][2][3][4] Here we report our results involving the addition of diethylzinc to aryl aldehydes using β- …”

Section: Introductionmentioning

confidence: 99%