Recent Developments in Transition Metal Catalyzed Intermolecular Hydroamination Reactions—A Breakthrough?

Nobis, Markus; Drießen‐Hölscher, Birgit

doi:10.1002/1521-3773(20011105)40:21<3983::aid-anie3983>3.0.co;2-8

Cited by 257 publications

(69 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Collapse of this species to the other terminus of the allyl system would result in racemization of the metallacycle. Analogous [1,3]-shifts proceeding through alternative azatrimethylenemethane isomers can also explain the E/Z isomerization ( Figure 7). Each [1,3]shift results in either inversion of the alpha stereocenter or E/Z isomerization, but not both.…”

Section: Racemizationmentioning

confidence: 91%

“…Initial β-hydride elimination to generate zirconium hydride complex 34 is followed by intramolecular hydrozirconation of the enamide double bond to give η 2 -imine complex 35. A [1,3]-shift of the zirconium center then generates the MAD complex. 38 An alternative mechanism initiated by dissociation of the allene followed by intermolecular C-H activation does not fit the observation that metallacycle 7 forms MAD complex 14 even in the presence of DIC (path b).…”

Section: Monoazadiene Complex Formationmentioning

confidence: 99%

“…The E/Z isomerization and racemization of the diaryl-metallacycles occur simultaneously in both the zirconocene system and the ebthi system, so mechanisms that explain the E/Z isomerization but do not allow for racemization (eqs 8 and 9) are unlikely. On the basis of preliminary DFT calculations, we proposed a [1,3]-shift mechanism involving coordination of the exocyclic olefin to the zirconium to form an η 4 -azatrim-ethylenemethane complex 32 as either an intermediate or a transition state (Scheme 11, eq 6). Collapse of this species to the other terminus of the allyl system would result in racemization of the metallacycle.…”

Section: Racemizationmentioning

confidence: 99%

“…To try to observe individual [1,3]-shifts, matched and mismatched met-allacycles 20 and 21 were synthesized by treatment of enantiopure ebthi imido complex (R,R)-1 with (R)-and (S)-diphenylallene, respectively. These isomers correspond to structures A and B in Figure 7.…”

Section: Matched and Mismatched Rearrangementsmentioning

confidence: 99%

See 3 more Smart Citations

Rearrangements and Stereomutations of Metallacycles Derived from Allenes and Imidozirconium Complexes

et al. 2005

View full text Add to dashboard Cite

The mechanisms of the rearrangements and stereoinversion of azametallacyclobutenes generated via [2+2] cycloaddition of allenes and imidozirconium complexes have been studied. Metallacycles derived from allenes bearing β-hydrogen atoms racemize at room temperature by reversible β-hydride elimination, a process which is also responsible for their eventual conversion to monoazadiene complexes. Metallacycles derived from diarylallenes racemize by reversible thermal bond homolysis at 95 °C; racemization of these metallacycles is also catalyzed by mild oxidants.

show abstract

Section: Racemizationmentioning

confidence: 91%

Section: Monoazadiene Complex Formationmentioning

confidence: 99%

Section: Racemizationmentioning

confidence: 99%

Section: Matched and Mismatched Rearrangementsmentioning

confidence: 99%

See 2 more Smart Citations

Rearrangements and Stereomutations of Metallacycles Derived from Allenes and Imidozirconium Complexes

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Moreover, intermolecular processes are generally much more difficult to achieve and far less developed than intramolecular processes. Several different types of homogeneous catalysts have been reported for hydroamination reactions of alkynes [3]. Compared with homogeneous catalysts, only a handful of heterogeneous catalysts have been reported.…”

Section: Introductionmentioning

confidence: 99%

Hydroamination of Terminal Alkynes by Amines Catalyzed by Copper Heteropoly Salts: A Simple Approach Towards Imine Synthesis

Shanbhag¹,

Palraj²,

Halligudi³

2008

TOOCJ

View full text Add to dashboard Cite

Abstract:The hydroamination reaction offers a very attractive route for the synthesis of alkylated amines and their derivatives with no byproduct formation. Heterogeneous intermolecular hydroamination reactions of alkynes with aromatic amines using different inexpensive copper salts of hetropolyacid catalysts were investigated. Among heteropoly salts, copper salts of silicotungstic acid showed highest activity. Reactivity of aromatic amines increased with increase in its basicity. Acidity in heterogeneous catalyst can act as promoter in hydroamination of alkynes.

show abstract

Hydroamination of Alkenes

Reznichenko

Hultzsch

2015

Organic Reactions

View full text Add to dashboard Cite

The addition of an amine NH‐functionality to alkenes (including vinyl arenes, conjugated dienes, allenes or ring‐strained alkenes), the so‐called hydroamination, represents a simple and highly atom‐economical approach for the synthesis of nitrogen‐containing products. A large variety of catalyst systems are available, ranging from alkali, alkaline earth, rare earth, Group 4 and Group 5 metals, to late transition metal catalysts, and, less prominent, Brønsted and Lewis acid‐based catalyst systems. The mode of operation of these catalyst systems can vary significantly and the different reaction mechanisms and the scope and limitations are discussed. While intramolecular hydroamination reactions can be readily achieved with a large number of catalyst systems, significantly fewer examples for the more challenging intermolecular hydroamination are known, especially for unactivated alkenes. The stereoselective hydroamination has also received significant attention due to the importance of chiral nitrogen‐containing molecules in pharmaceutical industry. A variety of highly selective chiral catalyst systems have been developed for intramolecular hydroaminations, while examples of intermolecular asymmetric hydroaminations are scarce. Hydroamination in the context of this review article is defined as the addition of HNR 2 across a non‐activated, unsaturated carbon‐carbon multiple bond. This review focuses on the hydroamination reaction of simple, non‐activated alkenes. The addition of amines to slightly activated alkenes, such as vinyl arenes, 1,3‐dienes, strained alkenes (norbornene derivatives, methylenecyclopropenes) and allenes is closely related and is covered as well. However, hydroamination reactions of alkynes and Aza‐Michael reactions involving the addition of an N‐H fragment across the conjugated or otherwise activated double bond of a Michael acceptor are not covered. The scope of amine types includes ammonia, primary and secondary aliphatic and aromatic amines, azoles, and hydrazines. N ‐Protected amines, such as ureas, carboxamides, and sulfonamides are covered as well, as they are important substrates for metal‐free and late transition metal‐based catalysts. The literature through January 2011 will be covered with two selected references from 2012 (comprising Table 3D). A supplemental reference list is provided for reports appearing February 2011 through April 2015. The chapter is organized by the nature of the carbon unsaturation to which the amine is added. Ranging from less reactive substrates such as ethylene and unactivated alkenes, to slightly activated substrates, such as vinyl arenes, and more activated substrates, including conjugated dienes, allenes and strained alkenes. Enantioselective hydroamination reactions, an area that has seen significant progress over the past decade, are discussed next. Finally, tandem hydroamination/carbocyclization reactions of aminodialkenes provide rapid access to complex alkaloidal skeletons. The tables at the end of the chapter are separated into five main sections: achiral intermolecular hydroamination, achiral intramolecular hydroamination, enantioselective intermolecular hydroamination, enantioselective intramolecular hydroamination, and tandem hydroamination/carbocyclization. Within the first four sections the tables are further divided into subsections based on the participating alkene, i.e. alkenes, vinyl arenes, dienes, allenes, and strained alkenes.

show abstract

Recent Developments in Transition Metal Catalyzed Intermolecular Hydroamination Reactions—A Breakthrough?

Cited by 257 publications

References 12 publications

Rearrangements and Stereomutations of Metallacycles Derived from Allenes and Imidozirconium Complexes

Rearrangements and Stereomutations of Metallacycles Derived from Allenes and Imidozirconium Complexes

Hydroamination of Terminal Alkynes by Amines Catalyzed by Copper Heteropoly Salts: A Simple Approach Towards Imine Synthesis

Hydroamination of Alkenes

Contact Info

Product

Resources

About