Enantioselective 6-endo-trig Wacker-type cyclization of 2-geranylphenols: application to a facile synthesis of (−)-cordiachromene

Takenaka, Kazuhiro; Tanigaki, Yugo; Patil, Mahesh L.; Rao, Changqing; Takizawa, Shinobu; Suzuki, Takayoshi; Sasai, Hiroaki

doi:10.1016/j.tetasy.2010.04.060

Cited by 42 publications

(18 citation statements)

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“…The enantiomers were separated using a Daicel Chiralpak AD column [2 cm Φ × 25 cm, EtOH, 4 mL/min, 235 nm]: T 1 = 16 min for ( P,R,R )‐ 1 f and T 2 = 24 min for ( M,S,S )‐ 1f . ( P,R,R )‐ 1 f : [α] D = −115.8 ( c = 0.82, CHCl 3 ). ( M,S,S )‐ 1f : [α] D = +119.4 ( c = 0.13, CHCl 3 ).…”

Section: Methodsmentioning

confidence: 99%

“…[14][15][16] Recently, we succeeded in the development of the cyclative diacetoxylation of alkynyl cyclohexadienones involving an unusual Pd enolate umpolung. 17 In addition, 5-endo-trig-type cyclization of 3-alkenoic acids, 18,19 oxidative allylic C À H esterification of 4-alkenoic acids, 20 and other asymmetric Pdcatalyzed reactions [21][22][23][24] are also feasible. In these processes, i-Pr-SPRIX 1d displayed the best performance.…”

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confidence: 99%

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Structural Features and Asymmetric Environment of i‐Pr‐SPRIX Ligand

et al. 2015

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Novel chiral diisopropyl spiro bis(isoxazoline) ligands, anti-i-Pr-SPRIX and syn-i-Pr-SPRIX, were designed and synthesized. Their catalytic utility, X-ray crystallographic analyses, and complexation studies demonstrated the structural features of tetraisopropyl spiro bis(isoxazoline) ligand, i-Pr-SPRIX, which is a prominent ligand in various enantioselective Pd catalytic processes: All i-Pr groups work in collaboration to create an effective asymmetric environment.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Structural Features and Asymmetric Environment of i‐Pr‐SPRIX Ligand

et al. 2015

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“…82 They discovered that a catalyst mixture consisting of Pd(TFA) 2 / 149a and 4 equivalents of BQ afforded six-membered ring 150 in 55% yield and 54% ee. The six- membered ring was formed preferentially to the five-membered ring, a feature observed in other oxycyclization reactions that employ this ligand class.…”

Section: Enantioselective Reactions Involving Oxypalladationmentioning

confidence: 99%

Palladium(II)-Catalyzed Alkene Functionalization via Nucleopalladation: Stereochemical Pathways and Enantioselective Catalytic Applications

2011

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“…Sasai and co-workers reported an enantioselective synthesis of (−)-cordiachromene 92 by using 6-endo-trig-Wacker-type oxidative cyclization of 2-geranylphenols without using any protecting groups. 30 Before they started the actual synthesis of cordiachromene, the reaction condition was optimized using 2-geranyl phenol 86 as the starting compound, which produced the corresponding chromene 88 in 55% yield with 54% ee in the presence of 11 mol % iPr-SPRIX 87, 10 mol % Pd(OCOCF 3 ) 2 and 4 equiv of p-benzoquinone in dichloromethane as solvent at 60°C. Notably, the 5-exo-trig cyclization product 89 was also obtained in 11% yield with 18% ee (Scheme 42).…”

Section: Acs Catalysismentioning

confidence: 99%

Catalytic Synthesis of 2H-Chromenes

et al. 2015

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2H-Chromenes (2H-1-benzopyran derivatives) display a broad spectrum of biological activities. The 2H-chromene substructure is an important structural motif present in a variety of medicines, natural products, and materials showing unique photophysical properties. Hence, the structural importance of the benzopyran moiety has elicited a great deal of interest in the field of organic synthesis and chemical biology to develop new and improved synthesis of these molecular skeletons. This review gives an up-to-date overview of different catalytic methodologies developed for the synthesis of 2H-chromenes and is structured around the three main approaches applied in catalytic 2H-chromene synthesis: (I) catalysis with (transition) metals, (II) metal-free Brønsted and Lewis acid/base catalysis, which includes examples of nonenantioselective organocatalysis, and (III) enantioselective organo-catalysis. The section in which the metal-catalyzed reactions are discussed describes different ring-closing strategies based on (transition) metal catalysis, including a few enantioselective approaches. For most of these reactions, plausible mechanisms are delineated. Moreover, synthesis of some natural products and medicinally important drugs are included. Specific advantages and disadvantages of the several synthetic methodologies are discussed. The review focuses on catalytic 2H-chromene synthesis. However, for a complete overview, synthetic routes involving some stoichiometric steps and reactions producing ring-scaffolds that are closely related to 2H-chromenes are also included.

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Enantioselective 6-endo-trig Wacker-type cyclization of 2-geranylphenols: application to a facile synthesis of (−)-cordiachromene

Cited by 42 publications

References 42 publications

Structural Features and Asymmetric Environment of i‐Pr‐SPRIX Ligand

Structural Features and Asymmetric Environment of i‐Pr‐SPRIX Ligand

Palladium(II)-Catalyzed Alkene Functionalization via Nucleopalladation: Stereochemical Pathways and Enantioselective Catalytic Applications

Catalytic Synthesis of 2H-Chromenes

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