Catalytic Asymmetric Aldol-Type Reactions Using a Chiral (Acyloxy)borane Complex

Ishihara, Kazuaki; Maruyama, Tadashi; Mouri, Makoto; Gao, Qingzhi; Furuta, Kyoji; Yamamoto, Hisashi

doi:10.1246/bcsj.66.3483

Cited by 61 publications

(23 citation statements)

References 29 publications

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“…Yamamoto has demonstrated the potential of tartratederived chiral acyloxyboranes, such as (1)- (5), to serve as highly efficient enantioselective catalysts for a variety of Lewis acid mediated processes including the Diels-Alder, [3][4][5][6][7] Mukaiyama aldol, 8,9 Sakurai-Hosomi, 10,11 and hetero-Diels-Alder 12,13 reactions. The potential of CAB catalysis for a hetero-Diels-Alder reaction between the keto aldehyde (6) and the diene (9) was recognized by us in 1992.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The potential of CAB catalysis for a hetero-Diels-Alder reaction between the keto aldehyde (6) and the diene (9) was recognized by us in 1992. 14 In a brief investigation, a solution of (6), (9), and the CAB (1) (0.1 equiv.) in dichloromethane was stirred at -78°for 18 h. However, this resulted only in recovery (89%) of the keto aldehyde (6), while a similar reaction employing (1) (2.5 equiv.)…”

Section: Introductionmentioning

confidence: 99%

“…of 60% (Scheme 1). It was assumed that (13) arose from a Mukaiyama aldol-like reaction and the failure to observe any reaction with catalytic quantities of the CAB complex was rationalized by assuming that coordination of the complex to other basic sites of the anthraquinone molecule, such as the oxygens of the quinone carbonyl and the peri methoxy groups, was inhibiting the desired reaction between the C2 formyl group of (6) and the diene (9). Subsequent to our initial investigations, Yamamoto reported the successful catalysis of hetero-Diels-Alder reactions between simple aldehydes and dienes using CAB complexes.…”

Section: Introductionmentioning

confidence: 99%

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Experiments Directed Towards the Synthesis of Anthracyclinones. XXXIV Hetero-Diels - Alder Reactions Using Chiral Boron and Titanium Reagents

Bercich¹,

Cambie²,

Rutledge³

1999

Aust. J. Chem.

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Reactions between benzaldehyde or o-anisaldehyde and a series of silyloxy dienes catalysed by the chiral acyl- oxyborane (CAB) complex (4) give high yields of enantioselective products from a Mukaiyama aldol rather than a hetero-Diels–Alder reaction. Attempts to effect a similar catalytic reaction with anthraquinone aldehydes were unsuccessful but use of 2 equiv. of the CAB complex (1) followed by cyclization promotes a formal hetero- Diels–Alder reaction between the aldehyde (7) and the diene (12) to give the dihydropyrone (24) in 45% yield and with a 79% e.e. in favour of the 2'R enantiomer. Hetero-Diels–Alder reactions between the aldehyde (7) and the diene (12) using the chiral titanium complexes Ti[(R)-BINOL]Cl 2 , Ti[(R,R)-TADDOL]Cl 2 and Ti[(R)-BINOL] 2 have been investigated. The first two complexes promote the reaction at −30 and −78° respectively but with low induced enantioselectivities.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experiments Directed Towards the Synthesis of Anthracyclinones. XXXIV Hetero-Diels - Alder Reactions Using Chiral Boron and Titanium Reagents

Bercich¹,

Cambie²,

Rutledge³

1999

Aust. J. Chem.

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“…The crude aldimines were recrystallized from ethanol to give the pure materials. Ketene silyl acetals were prepared according to the literature (7,8). (R)-6,6Ј-bis(pentafluoroethyl) 2 -1,1Ј-binaphthene-2,2Ј-diol (BINOL), (R)-3,3Ј-(m-CF 3 C 6 H 4 ) 2 BINOL, (R)-3,3Ј-Br 2 BINOL, and (R)-3,3Ј-I 2 BINOL were prepared according to the literature (9-11).…”

mentioning

confidence: 99%

Air-stable, storable, and highly efficient chiral zirconium catalysts for enantioselective Mannich-type, aza Diels–Alder, aldol, and hetero Diels–Alder reactions

Kobayashi

Ueno

Saitō

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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For the synthesis of optically active compounds, chiral catalysts have attracted much attention because large quantities of optically active molecules can be prepared from a small amount of a chiral source. However, many chiral catalysts are often unstable in air (oxygen) and͞or in the presence of water. This is especially the case in chiral Lewis acid catalysis, because most Lewis acids are air-and moisture-sensitive. Therefore, many catalysts are prepared in situ in an appropriate solvent just before use, and they cannot be stored for extended periods. We have developed air-stable, storable, and highly efficient chiral zirconium Lewis acids. The catalysts promoted asymmetric Mannich-type, aza Diels-Alder, aldol, and hetero Diels-Alder reactions efficiently with high enantioselectivities. A key to stabilizing the catalysts is an appropriate combination of chiral zirconium Lewis acids with molecular sieves, and the zirconium-molecular sieves-combined catalysts can be stored for extended periods in air at room temperature without loss of activity. Moreover, it has been demonstrated that the catalysts can be recovered and reused.

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Arylboron Compounds as Acid Catalysts in Organic Synthetic Transformations

Ishihara¹,

Yamamoto²

1999

Eur. J. Org. Chem.

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228

122

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Arylboron compounds, ArnB(OH)3–n (n = 1–3), bearing electron‐withdrawing aromatic groups such as triarylboranes, diarylborinic acids, and arylboronic acids represent a new class of air‐stable and water‐tolerant Lewis acid or Brønsted acid catalysts in organic synthesis. In particular, while tris(pentafluorophenyl)borane has primarily been used as a co‐catalyst in metallocene‐mediated olefin polymerization, its potential as a Lewis acid catalyst for organic transformation is now much more extensive. Diarylborinic acids and arylboronic acids have shown themselves to be powerful tools in the design of chiral boron catalysts. This article provides a comprehensive summary of the organic transformations catalyzed by arylboron compounds as acids.

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Catalytic Asymmetric Aldol-Type Reactions Using a Chiral (Acyloxy)borane Complex

Cited by 61 publications

References 29 publications

Experiments Directed Towards the Synthesis of Anthracyclinones. XXXIV Hetero-Diels - Alder Reactions Using Chiral Boron and Titanium Reagents

Experiments Directed Towards the Synthesis of Anthracyclinones. XXXIV Hetero-Diels - Alder Reactions Using Chiral Boron and Titanium Reagents

Air-stable, storable, and highly efficient chiral zirconium catalysts for enantioselective Mannich-type, aza Diels–Alder, aldol, and hetero Diels–Alder reactions

Arylboron Compounds as Acid Catalysts in Organic Synthetic Transformations

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