Preparation of Enantiopure Norbornane Ligands Bearing Both (2S,3S)-Bis(phosphinomethyl) and 7-syn-Oxygen Functional Groups and an Application to Rhodium-Catalyzed Asymmetric Hydrogenation

Morimoto, Toshiaki; Yamazaki, Akira; Achiwa, Kazuo

doi:10.1248/cpb.52.1367

Cited by 17 publications

(6 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Table 3. According to the procedure reported previously, 32,33) the hydrogenation product 16 was isolated and the enantiomeric excess was determined by HPLC after conversion to its N-benzoyl derivative. All the results are summarized in Table 3.…”

mentioning

confidence: 99%

Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

et al. 2004

Self Cite

View full text Add to dashboard Cite

Development of efficient methods for catalytic enantioselective synthesis has been an important subject for the practical synthesis of optically active organic compounds.1) Numerous methods of enantioselective synthesis employing various catalysts such as transition metal complexes coordinated with many types of chiral ligands have been reported for more than three decades. [1][2][3][4][5][6] For the development of efficient chiral catalysts, creation of new types of ligands is a most significant strategy. Among various types of chiral ligands, diphosphines are the most effective and are widely applicable in the catalytic asymmetric hydrogenation of prochiral compounds such as olefins, ketones, and imines using transition metal (rhodium, ruthenium, iridium, etc.) complexes as catalyst. We previously proposed a novel idea, "respective control concept" for designing new chiral ligands, 7-10) and developed efficient diphosphine ligands such as (2S-cis)-4-(dicyclohexylphosphino)-2-[(diphenylphosphino)methyl]-1-pyrrolidinecarboxylic acid 1,1-dimethylethyl ester (BCPM) and its analogs, 8,[11][12][13] (4R-trans)-[(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis[bis(4-methoxy-3,5-dimethylphenyl)phosphine] (MOD-DIOP) and its analogs, [14][15][16][17] etc. (Fig. 1) for rhodium-catalyzed asymmetric hydrogenation of some prochiral ketones (ketopantolactone, a-and bamino ketones, etc.), and olefins (itaconic acid and its derivatives, N-acyldehydroamino acids, etc.). Furthermore, we revealed that phosphines bearing electron-donating groups such as cyclohexyl groups, p-(dimethylamino)phenyl groups, and p-methoxy-m,mЈ-dimethylphenyl groups enhance not only the catalytic activity but also the enantioselectivity in the rhodium-catalyzed hydrogenations. The p-methoxym,mЈ-dimethylphenyl (abbreviated to MOD) group was found to be a useful component for developing efficient ligands on the basis of its steric effect (m-Me) as well as its electronic effect (p-MeO, m-Me).15) We also reported in preliminary communications the design and preparation of axially chiral diphosphines, [18][19][20][21] which were found to be very efficient ligands for ruthenium-catalyzed asymmetric hydrogenation of a b-keto ester or rhodium-catalyzed asymmetric hydrogenation of an a-amino ketone. In this article we describe in detail the synthesis of optically pure 3,3Ј-dimethoxy-2,2Ј,4,4Ј-tetramethyl-1,1Ј-biphenyls 8a-c bearing one or two 6,(6Ј)-dicyclohexylphosphino group(s) and/or 6,(6Ј)-diphenylphosphino group(s), and an application to rhodium-catalyzed asymmetric hydrogenation. Results and DiscussionThe synthetic route of axially dissymmetric biphenyldiphosphine ligands 8a-c bearing one or two dicyclohexylphosphino group(s) and/or one or two diphenylphosphino group(s) is described in Chart 1 (8a-c were abbreviated to BIMOP, Cy-BIMOP, and MOC-BIMOP, respectively). Iodination of 2,6-dimethylnitrobenzene (1) was carried out selectively at the 3-position by heating with iodine at 90°C for 4 d in the presence of periodic acid in acetic acid containing d...

show abstract

mentioning

confidence: 99%

Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

et al. 2004

Self Cite

View full text Add to dashboard Cite

show abstract

“…[11] It was shown that upon treatment of norbornenones with bromine the corresponding bromolactones were obtained in good yields. When exposed to silver(I) salts, these structures undergo a rearrangement via a non-classical cation to give, upon treatment with basic methanol, norbornenyl diester derivatives.…”

Section: Resultsmentioning

confidence: 99%

Towards the Synthesis of Massadine: A Unified Strategy for the Stereoselective Synthesis of the Carbocyclic C,D‐Ring Subunit

Breder¹,

Chinigo²,

Waltman³

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

Massadine is a hexacyclic marine natural product, which belongs to the family of pyrrole-imidazole alkaloids. Herein, we describe a unified approach to the C,D-ring subunit of this sponge metabolite based on the exploitation of a norbornene scaffold for the stereocontrolled construction of massadine's carbon skeleton. Highlights of the sequence presented include the application of a stereospecific norbornyl rearrangement for facile introduction of an oxygen at the C7-position within the norbornene nucleus, a highly regioselective and end group differentiating ozonolytic scission of a C-C double bond, and an oxidative decarboxylation reaction for the installation of the hindered secondary C2-alcohol function. Furthermore, the iterative assembly of the two guanidine entities as well as the implementation of the spirocyclic junction between the C- and the D-rings are described. Collectively, these key transformations permit an entry to an appropriately functionalized carbon framework, which will serve as a starting point for our efforts toward the completion of the synthesis of massadine.

show abstract

“…Compared to NAPHOS, Ph-o-NAPHOS has a more rigid structure and provides higher enantioselectivities. The chiral norbornane diphosphine ligands, 15 and 16, were reported by Morimoto, and applied in Rh-catalyzed enantioselective hydrogenation [84]. Zhou reported a family of chiral spirodiphosphine ligands such as SDP, containing 1,1'-spirobi-indane as a new scaffold, which are effective for the hydrogenation of simple ketones (Fig.…”

Section: Other Bisphosphine Ligandsmentioning

confidence: 99%

The other Bisphosphine Ligands for Enantioselective Alkene Hydrogenation

Chi

Tang

Zhang

2006

The Handbook of Homogeneous Hydrogenation

View full text Add to dashboard Cite

26The other Bisphosphine Ligands for Enantioselective Alkene Hydrogenation CHEP ligand, which was successfully applied in both Rh-and Ru-catalyzed enantioselective hydrogenation [7]. Schmid et al. reported BIPHEMP [8] and ligands, both of which were successfully applied in many Ru-catalyzed hydrogenations. Achiwa also developed several atropisomeric ligands such as BIMOP [10], FUPMOP [11], and MOC-BIMOP ( Fig. 26.1) [12].Modification of the electronic and steric properties of BINAP, BIPHEMP, and MeO-BIPHEP can lead to the development of new efficient atropisomeric ligands ( Fig. 26.1). In fact, Takaya has found that a modified BINAP ligand, H 8 -BINAP, provides better enantioselectivity than BINAP in the Ru-catalyzed hydrogenation of unsaturated carboxylic acids [13]. Mohr has developed a bis-steroidal bisphosphine 1, which has shown similar catalytic results to BINAP in the Ru-catalyzed enantioselective hydrogenation [14]. Hiemstra has developed a dibenzofuranbased bisphosphine BIFAP, which has shown excellent enantioselectivity in the Ru-catalyzed hydrogenation of methyl acetoacetate [15]. The dihedral angle of the biaryl backbone is expected to have a strong influence on the enantioselectivity. Another chiral biaryl bisphosphine ligand, SEGPHOS, was developed in Takasago. The ligand, which possesses a narrower dihedral angle than BINAP, has provided greater enantioselectivity than BINAP in the Ru-catalyzed hydrogenation of a wide variety of carbonyl compounds [16]. Chan [17 a] and Genêt [17 b, c] have reported a closely related ligand bisbenzodioxanPhos (SYNPHOS) independently. In order systematically to investigate the influence of the dihedral angle of biaryl ligands on enantioselectivity, Zhang has developed a series of TunePhos ligands with tunable dihedral angles. When the TunePhos ligands are applied in the Ru-catalyzed enantiomeric hydrogenation of b-keto esters, the ee-values obtained fluctuate with the different dihedral angles of the TunePhos ligands [18]. C4-TunePhos shows comparable or superior enantioselectivity to BINAP in Ru-catalyzed hydrogenation of b-keto esters. More applications of the TunePhos ligands have shown that different asymmetric catalytic reactions may require a different TunePhos ligand with a different dihedral angle. When TunePhos ligands are applied in the Ru-catalyzed hydrogenation of enol acetates, C2-TunePhos is the best ligand in terms of enantioselectivity [19]. However, C3-TunePhos provided the best enantioselectivities for the synthesis of cyclic b-amino acids [20], and the hydrogenation of aphathalimide ketones [21]. Genêt and Marinetti have developed a non-C 2 symmetric biaryl bisphosphine, MeO-NAPhePHOS, which has shown comparable results to C 2 -symmetric biaryl bisphosphine in Ru-catalyzed hydrogenation [22]. Structural variation of BINAP or MeO-BIPHEP can also be made on the aromatic rings of the biaryl backbone ( Fig. 26.1). For example, the aromatic rings can be replaced by five-or six-membered heteroaromatic rings. Sannicolò et al. have discovered a series of...

show abstract

Preparation of Enantiopure Norbornane Ligands Bearing Both (2S,3S)-Bis(phosphinomethyl) and 7-syn-Oxygen Functional Groups and an Application to Rhodium-Catalyzed Asymmetric Hydrogenation

Cited by 17 publications

References 14 publications

Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

Towards the Synthesis of Massadine: A Unified Strategy for the Stereoselective Synthesis of the Carbocyclic C,D‐Ring Subunit

The other Bisphosphine Ligands for Enantioselective Alkene Hydrogenation

Contact Info

Product

Resources

About