Chelation-assisted β-alkylation of α,β-unsaturated ketone using Rh(I) catalyst and dialkyl amine

Jun, Chul Ho; Moon, Choong Woon; Kim, Young Min; Lee, Hyuk; Lee, Jun Hee

doi:10.1016/s0040-4039(02)00769-4

Cited by 54 publications

(18 citation statements)

References 26 publications

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“…Jun was the first to report on the Rh-catalyzed alkylation of an α,β-unsaturated carbonyl derivative, though limited scope and isomeric product mixtures were observed. xviii …”

Section: Chelation-assisted Functionalization Of Olefinsmentioning

confidence: 99%

Rhodium Catalyzed Chelation-Assisted C–H Bond Functionalization Reactions

Colby¹,

Tsai²,

et al. 2011

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Conspectus Over the last several decades, researchers have achieved remarkable progress in the field of organometallic chemistry. The development of metal-catalyzed cross-coupling reactions represents a paradigm shift in chemical synthesis, and today synthetic chemists can readily access carbon-carbon and carbon-heteroatom bonds from a vast array of starting compounds. Although we cannot understate the importance of these methods, the required pre-functionalization to carry out these reactions adds cost and reduces the availability of the starting reagents. The use of C-H bond activation in lieu of pre-functionalization has presented a tantalizing alternative to classical cross-coupling reactions. Researchers have met the challenges of selectivity and reactivity associated with the development of C-H bond functionalization reactions with an explosion of creative advances in substrate and catalyst design. Literature reports on selectivity based on steric effects, acidity, and electronic and directing group effects are now numerous. Our group has developed an array of C-H bond functionalization reactions that take advantage of a chelating directing group, and this Account surveys our progress in this area. The use of chelation control in C-H bond functionalization offers several advantages with respect to substrate scope and application to total synthesis. The predictability and decreased dependence on the inherent stereoelectronics of the substrate generally result in selective and high yielding transformations with broad applicability. The nature of the chelating moiety can be chosen to serve as a functional handle in subsequent elaborations. Our work began with the use of Rh(I) catalysts in intramolecular aromatic C-H annulations, which we further developed to include enantioselective transformations. The application of this chemistry to the simple olefinic C-H bonds found in α,β-unsaturated imines allowed access to highly substituted olefins, pyridines, and piperidines. We observed complementary reactivity with Rh(III) catalysts and developed an oxidative coupling with unactivated alkenes. Further studies on the Rh(III) catalysts led us to develop methods for the coupling of C-H bonds to polarized π bonds such as those in imines and isocyanates. In several cases the methods that we have developed for chelation-controlled C-H bond functionalization have been applied to the total synthesis of complex molecules such as natural products, highlighting the utility of these methods in organic synthesis.

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“…Jun was the first to report on the Rh-catalyzed alkylation of an α,β-unsaturated carbonyl derivative, though limited scope and isomeric product mixtures were observed. xviii …”

Section: Chelation-assisted Functionalization Of Olefinsmentioning

confidence: 99%

Rhodium Catalyzed Chelation-Assisted C–H Bond Functionalization Reactions

Colby¹,

Tsai²,

et al. 2011

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“…However, diluting the reaction mixture two-fold significantly enhanced the yield to 76% (entry 10), which is comparable to the yield observed in the reaction with pre-formed imine (see eq 1). Although catalytic in situ imine formation has been utilized for Rh(I) catalysis, 18 to the best of our knowledge, this is the first example of using catalytic in situ imine formation for Rh(III)-catalyzed C-H functionalization.…”

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confidence: 99%

Facile Synthesis of Unsymmetrical Acridines and Phenazines by a Rh(III)-Catalyzed Amination/Cyclization/Aromatization Cascade

et al. 2013

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New formal [3 + 3] annulations have been developed to obtain acridines and phenazines from aromatic azides and aromatic imines and azobenzenes, respectively. These transformations proceed through a cascade process of Rh(III)-catalyzed amination followed by intramolecular electrophilic aromatic substitution and aromatization. Acridines can be directly prepared from aromatic aldehydes by in situ imine formation using catalytic benzylamine.

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“…[7] Though catalytic conjugate addition of alkenes has been recognized as a potentially powerful synthetic methodology in forming tetrasubstituted olefins, generally applicable conjugate addition of simple olefins to α,β-unsaturated carbonyl compounds has been hampered by lack of reactivity of the olefin substrates and due to the formation of homocoupling and other byproducts. Chelate-assisted C–H insertion [8] and cross coupling methods [9] are among the most notable advances in catalytic coupling reaction of enones with simple alkenes. Ni-catalyzed conjugate addition and allylic substitution reactions of simple alkenes have also been reported recently.…”

mentioning

confidence: 99%

Tetrasubstituted Olefins through the Stereoselective Catalytic Intermolecular Conjugate Addition of Simple Alkenes to α,β‐Unsaturated Carbonyl Compounds

Kwon¹,

Lee²,

Yi³

2011

Angew Chem Int Ed

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Recent efforts in designing expeditious catalytic synthesis of tetrasubstituted olefins have in part been stimulated by growing needs for developing generally applicable methods for tamoxifen analogs (anti-breast cancer drug) as well as for photo-responsive organic materials and molecular devices.[1] A number of different catalytic methods have been developed to synthesize tetrasubstituted olefins, including: Suzuki-type Pd-catalyzed coupling reactions,[2] Ni- and Rh-catalyzed exocyclization methods,[3] Ni- and Pd-catalyzed nucleophilic coupling reactions of alkynes[4] and of alkyne-to-arylboronic acids,[5] Ti-catalyzed tandem alkyne-epoxide-ethyl acetate coupling,[6] and the ring-closing olefin metathesis by using Grubbs catalyst.[7] Though catalytic conjugate addition of alkenes has been recognized as a potentially powerful synthetic methodology in forming tetrasubstituted olefins, generally applicable conjugate addition of simple olefins to α,β-unsaturated carbonyl compounds has been hampered by lack of reactivity of the olefin substrates and due to the formation of homocoupling and other byproducts. Chelate-assisted C–H insertion[8] and cross coupling methods[9] are among the most notable advances in catalytic coupling reaction of enones with simple alkenes. Ni-catalyzed conjugate addition and allylic substitution reactions of simple alkenes have also been reported recently.[10] We recently discovered that the cationic complex [(C6H6)(CO)(PCy3)RuH]+BF4− (1) is a highly effective catalyst precursor for the coupling reactions of arylketones and alkenes involving C–H activation.[11] Herein we report a novel catalytic synthesis of tetrasubstituted olefins from the intermolecular conjugate addition reaction of simple olefins to α,β-unsaturated carbonyl compounds.

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Chelation-assisted β-alkylation of α,β-unsaturated ketone using Rh(I) catalyst and dialkyl amine

Cited by 54 publications

References 26 publications

Rhodium Catalyzed Chelation-Assisted C–H Bond Functionalization Reactions

Rhodium Catalyzed Chelation-Assisted C–H Bond Functionalization Reactions

Facile Synthesis of Unsymmetrical Acridines and Phenazines by a Rh(III)-Catalyzed Amination/Cyclization/Aromatization Cascade

Tetrasubstituted Olefins through the Stereoselective Catalytic Intermolecular Conjugate Addition of Simple Alkenes to α,β‐Unsaturated Carbonyl Compounds

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