Assembly State of Catalytic Modules as Chiral Switches in Asymmetric Strecker Amino Acid Synthesis

Kato, Norihiro; Mita, Tsuyoshi; Kanai, Motomu; Therrien, Bruno; Kawano, Masaki; Yamaguchi, Kentaro; Danjo, Hiroshi; Sei, Yoshihisa; Sato, Akihiro; Furusho, Sanae; Shibasaki, Masakatsu

doi:10.1021/ja060841r

Cited by 115 publications

(56 citation statements)

References 9 publications

(9 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…66,68) induction ability from that of monomeric dinuclear complex (R a ,S,S)-2. 88,89) As a result, reactions run in CH 2 Cl 2 or (CH 2 Cl) 2 provided (S)-configuration of BINOLs (Table 7, entries 1, 2), and for all reactions run in CCl 4 or toluene gave (R)-BINOLs (entries 3-10, 12, 14).…”

Section: Comparison Of Our Dinuclear Vanadium(iv) and (V) Catalysts Wmentioning

confidence: 95%

Development of Dinuclear Vanadium Catalysts for Enantioselective Coupling of 2-Naphthols via a Dual Activation Mechanism

Takizawa

2009

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

Catalytic asymmetric reactions are among the most powerful synthetic methods to obtain optically active compounds.1,2) Recent challenges focus on the development of asymmetric catalysts for carbon-carbon bond-forming reactions with high activity and broad substrate generality, which lead to practical, efficient, and environmentally benign chemical syntheses. Dual activation systems for substrates such as nucleophiles and electrophiles lead to enhanced reaction rates and more specific control of the transition structure with respect to the catalyst's asymmetric environment. Dual activation catalyses can be classified into three categories ( Fig. 1): Type 1) dual activation using two different kinds of catalysts [3][4][5][6][7][8][9][10][11][12] ; Type 2) conjugated-type dual activation with a functional group such as a phosphate which has both acidic and basic sites in one functionality [13][14][15] ; and Type 3) dual activation by two catalytic sites in a single catalyst. For efficient dual activation of the substrates, a balance between these two functionalities in the catalyst is required. For example, in an acid-base type catalyst the selfquenching reaction of acidic and basic moieties on the catalyst can lead to its inactivation.We postulated that a chiral complex possessing two identical metal centers in a single molecule, which could activate two substrates simultaneously in a homolytic coupling reaction of 2-naphthol molecules, would enhance the reaction rate with high enantioselectivity. To achieve the new dual activation catalysis in an oxidative coupling reaction, we designed the catalyst (R a ,S,S)-1 42) bearing two active sites attached to a binaphthyl skeleton, taking advantage of the activation entropy (Fig. 2). Activation entropy strongly con- Development of Dinuclear Vanadium Catalysts for Enantioselective Coupling of 2-Naphthols via a Dual Activation MechanismShinobu TAKIZAWA This review describes our recent efforts in the development of chiral dinuclear vanadium complexes which work as dual activation catalysts for oxidative coupling of 2-naphthols. A chiral dinuclear vanadium(IV) complex (R a ,S,S)-1a possessing (S)-tert-leucine moieties at the 3,3 -positions of the (R)-binaphthyl skeleton was developed, and found to promote oxidative coupling of 2-naphthol to afford (S)-1,1 -bi-2-naphthol (BINOL) with 91% ee. To verify the dual activation mechanism, mononuclear vanadium(IV) complex (S)-10 was also prepared. Kinetic analysis revealed that the reaction rate of oxidative coupling of 2-naphthol promoted by (R a ,S,S)-1a is 48.3 times faster than that of (S)-10. In the coupling reaction, the two vanadium metals in the chiral complex activate two molecules of 2-naphthol simultaneously achieving a high reaction rate with high enantiocontrol. Since the dinuclear vanadium(IV) complex was found to be readily oxidized to afford a corresponding vanadium(V) species during preparation in air, a new synthetic procedure using VOCl 3 and a convenient one-pot procedure using VOSO 4 under O 2 have been applie...

show abstract

Section: Comparison Of Our Dinuclear Vanadium(iv) and (V) Catalysts Wmentioning

confidence: 95%

Development of Dinuclear Vanadium Catalysts for Enantioselective Coupling of 2-Naphthols via a Dual Activation Mechanism

Takizawa

2009

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

show abstract

“…Inspired by the role proximate metal centres play in increasing localised reagent concentration within enzymes, multimetallic species have been introduced to enhance several chemical transformations such as the Diels-Alder [167] and Stecker [168] reactions [169,170]. In olefin polymerisation, a wide range of bimetallic catalysts have been employed to try and find any cooperative effect that would arise from the complimentary interaction of the polymeric chain between the adjacent metal centres.…”

Section: Bimetallic Olefin Polymerisation Catalystsmentioning

confidence: 99%

Group 4 metal complexes for homogeneous olefin polymerisation: a short tutorial review

2015

View full text Add to dashboard Cite

The discovery of transition metal-catalysed polymerisation of olefins in the 1950s by Ziegler and Natta was of huge importance. Over the last 30 years, the interest in homogenous polymerisation has not only grown but has changed focus from primarily studying the metallocene complexes of Group 4 to widespread exploration of postmetallocene systems. This is a consequence of extensive patenting of the metallocene catalyst systems, as well as for general interest in the improvement of polyolefin catalysis. The plastics industry produces more than 10 7 tonnes of polyethylene, polypropylene and polystyrene each year worldwide, and the study of well-defined homogenous catalysts is invaluable in uncovering the mechanism of polymerisation and the fundamental properties of the active species. This short Tutorial Review gives an overview of homogenous transition metal Ziegler-Natta catalysis in general as well as an overview of a selection of Group 4 post-metallocene catalysts. An overview of the synthesis and reactions of alkyl cations relevant to olefin polymerisation is also given. Finally, this review summarises recent advances in bimetallic catalysts for olefin polymerisation.

show abstract

“…The high stereoselectivity would be rationalized by assuming a well-organized association in the transition state from a nonordered reaction mixture ensemble. [83][84][85] An enhanced catalytic activity was observed compared with the Sc(O i Pr) 3 /(S)-4a catalyst, allowing the reaction to take place with a range of imines 12, reaching completion after 1 h of stirring in ether at 0°C with 2 mol% of catalyst (Table 5). Of prime importance in the present catalytic system is the origin of the diastereoswitching.…”

Section: Catalytic Asymmetric Amination Of Succinimide Derivatives mentioning

confidence: 99%

Development of Atom-Economical Catalytic Asymmetric Reactions under Proton Transfer Conditions: Construction of Tetrasubstituted Stereogenic Centers and Their Application to Therapeutics

Kumagai

2011

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

The development of atom-economical catalytic asymmetric reactions based on two distinct sets of catalyst, a rare earth metal/amide-based ligand catalyst and a soft Lewis acid/hard Brønsted base catalyst, is reviewed. These catalytic systems exhibit high catalytic activity and stereoselectivity by harnessing a cooperative catalysis through hydrogen bond/metal coordination and soft-soft interactions/hard-hard interactions, respectively. The effectiveness of these cooperative catalysts is clearly delineated by the high stereoselectivity in reactions with highly coordinative substrates, and the specific activation of otherwise low-reactive pronucleophiles under proton transfer conditions. The rare earth metal/amide-based ligand catalyst was successfully applied to catalytic asymmetric aminations, nitroaldol (Henry) reactions, Mannich-type reactions, and conjugate addition reactions, generating stereogenic tetrasubstituted centers. Catalytic asymmetric amination and anti-selective catalytic asymmetric nitroaldol reactions were successfully applied to the efficient enantioselective synthesis of therapeutic candidates, such as AS-3201 and the b b 3 -adrenoreceptor agonist, showcasing the practical utility of the present protocols. The soft Lewis acid/hard Brønsted base cooperative catalyst was specifically developed for the chemoselective activation of soft Lewis basic allylic cyanides and thioamides, which are otherwise low-reactive pronucleophiles. The cooperative action of the catalyst allowed for efficient catalytic generation of active carbon nucleophiles in situ, which were integrated into subsequent enantioselective additions to carbonyl-type electrophiles.

show abstract

Assembly State of Catalytic Modules as Chiral Switches in Asymmetric Strecker Amino Acid Synthesis

Cited by 115 publications

References 9 publications

Development of Dinuclear Vanadium Catalysts for Enantioselective Coupling of 2-Naphthols via a Dual Activation Mechanism

Development of Dinuclear Vanadium Catalysts for Enantioselective Coupling of 2-Naphthols via a Dual Activation Mechanism

Group 4 metal complexes for homogeneous olefin polymerisation: a short tutorial review

Development of Atom-Economical Catalytic Asymmetric Reactions under Proton Transfer Conditions: Construction of Tetrasubstituted Stereogenic Centers and Their Application to Therapeutics

Contact Info

Product

Resources

About