Palladium-Catalyzed Regio- and Enantioselective Allylic Alkylation of Bis Allylic Carbonates Derived from Morita−Baylis−Hillman Adducts

Trost, Barry M.; Brennan, Megan K.

doi:10.1021/ol701585b

Cited by 66 publications

(13 citation statements)

References 16 publications

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“…60 Morita-Baylis-Hilman adducts can be deracemized by employing them as electrophiles in AAA reactions (Scheme 21). 61,62 This dynamic kinetic asymmetric transformation Scheme 19 AAA with a substituted pyrrole. (DYKAT) is achieved under Pd-catalysis using the Trost family of chiral ligands.…”

Section: Phenolsmentioning

confidence: 99%

Catalytic asymmetric allylic alkylation employing heteroatom nucleophiles: a powerful method for C–X bond formation

2010

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Section: Phenolsmentioning

confidence: 99%

Catalytic asymmetric allylic alkylation employing heteroatom nucleophiles: a powerful method for C–X bond formation

2010

Self Cite

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“…At this stage, the absolute configuration of the N,O‐acetal carbon atom was assigned to be S by analogy to our previous study 2. Interestingly, switching to the ligand ( R , R )‐ L2 10, 11 gave 6 in greater than 99 % ee in near quantitative yield (entry 2). This excellent ee value confirms the conservation of the stereochemical integrity of the N,O‐acetal in the RCM reaction, thus verifying the plausibility of the proposed concept.…”

Section: Methodsmentioning

confidence: 61%

Synthetic Strategy for Cyclic Amines: A Stereodefined Cyclic N,O‐Acetal as a Stereocontrol and Diversity‐Generating Element

Kim

Lim

et al. 2012

Angewandte Chemie

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Ringbildung: Eine neue Strategie zur Synthese cyclischer Amine nutzt ein stereochemisch definiertes cyclisches N,O‐Acetal als wichtigstes stereokontrollierendes und Diversität erzeugendes Element. Das Acetal, das seine stereochemische Integrität über alle katalytischen Umwandlungen bewahrt, wurde durch asymmetrische Hydroaminierung eines Alkoxyallens mit dem chiralen Liganden L* und anschließende Ringschlussmetathese erhalten.

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“…As it has been used for the synthesis of a variety of natural and unnatural products [4-6], the MBH reaction has become increasingly significant [3,[7][8][9][10][11][12][13][14][15][16][17][18][19]. However, the application of the MBH reaction had been limited in complex syntheses by slow reaction rates and low conversions [3,20] as well as problems in controlling absolute stereochemistry [8].…”

Section: Citationmentioning

confidence: 99%

A novel self-promoted Morita-Baylis-Hillman-like dimerization

Wongkhan

Luo

et al. 2010

Chin. Sci. Bull.

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While stable in CH 2 Cl 2 , hexane or THF, in the presence of MeOH, self-promoted dimerization of the triarylphosphine-alkene 1, a ligand for Pd-catalyzed reactions, produced an unusual racemic bis(phosphine) 2 in high yield. The reaction of 2 with Pd(dba) 2 , followed by oxidative addition of p-IC 6 H 4 NO 2 , yielded a trans-chelated Pd(II) aryl iodide complex. phosphine, ligand, palladium, DFT calculations, reaction mechanism Citation:Li Q, Wongkhan K, Luo X C, et al. A novel self-promoted Morita-Baylis-Hillman-like dimerization.The Morita-Baylis-Hillman (MBH) reaction [1,2] is a useful and atom-economical carbon-carbon bond forming reaction (Scheme 1), involving nucleophile catalyzed addition of an alkene, which is activated by an electron-withdrawing group, to an electrophile, typically an aldehyde or imine [3]. As it has been used for the synthesis of a variety of natural and unnatural products [4-6], the MBH reaction has become increasingly significant [3,[7][8][9][10][11][12][13][14][15][16][17][18][19]. However, the application of the MBH reaction had been limited in complex syntheses by slow reaction rates and low conversions [3,20] as well as problems in controlling absolute stereochemistry [8]. Theoretical and experimental studies have provided insight into how to increase the rate of this reaction [21][22][23][24][25]. Nucleophilic catalysts such as DABCO, DBU, and n-Bu 3 P are frequently employed [20]. Slow reaction rates [20], autocatalysis in the absence of proton donors [22], formation of dioxanones [26,27], and the rate acceleration observed in protic solvents [28][29][30][31][32] are intriguing aspects of the MBH reaction, and recent DFT studies have begun to provide useful mechanistic insights [33][34][35].Scheme 1 Morita-Baylis-Hillman (MBH) reaction. EWG: electronwithdrawing group.A few examples of dimerization reactions have been reported, but they require a catalyst [36][37][38][39], or high temperature [39], or high pressure [40]. We report the unusual case of a self-promoted dimerization of a triarylphosphine-substituted vinylphenyl-ketone 1, which we have been exploring as a ligand in Pd-catalyzed reactions [41][42][43].The dimerization of 1 (Scheme 2) occurs under ambient conditions in CH 2 Cl 2 /MeOH mixtures, requiring no additives, yielding dimer 2 in ca. 80% isolated yield. In situ NMR experiments and DFT calculations provide preliminary insight into the mechanism, including reaction order and solvent effects.Initially, we used different solvent combinations (CH 2 Cl 2 /hexane, THF/hexane, and CH 2 Cl 2 /MeOH) to grow crystals of 1. We obtained crystals of 1 (Figure 1 (a)) from CH 2 Cl 2 /hexane and THF/hexane, but were surprised to ob-

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Palladium-Catalyzed Regio- and Enantioselective Allylic Alkylation of Bis Allylic Carbonates Derived from Morita−Baylis−Hillman Adducts

Abstract: Morita-Baylis-Hillman diene adducts are used as substrates in the palladium-catalyzed asymmetric allylic alkylation reaction with oxygen and carbon nucleophiles in good regio- and enantioselectivity.

Cited by 66 publications

References 16 publications

Catalytic asymmetric allylic alkylation employing heteroatom nucleophiles: a powerful method for C–X bond formation

Catalytic asymmetric allylic alkylation employing heteroatom nucleophiles: a powerful method for C–X bond formation

Synthetic Strategy for Cyclic Amines: A Stereodefined Cyclic N,O‐Acetal as a Stereocontrol and Diversity‐Generating Element

A novel self-promoted Morita-Baylis-Hillman-like dimerization

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